Reptile Temperature and UVB Chart: Basking, Day and Night Temps for 59 Species

By Reptile Gear ReviewPublished Oct 12, 20263 min readHow we research

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A bearded dragon wants a basking surface of 40 to 45°C (104 to 113°F) and sits in UVB Ferguson zone 3 to 4; a leopard gecko needs a 32°C (90°F) basking spot and only zone 1 levels of UVB; a ball python wants 35 to 40°C at the basking spot, 28 to 30°C by day and 24 to 26°C at night. Those figures come from the UV-Tool, a database of 254 species published in the Journal of Zoo and Aquarium Research in 2016 by Frances Baines and colleagues for the British and Irish zoo association's reptile working group.

The chart below gives those figures for 59 common pet reptiles, with the Merck Veterinary Manual's temperature range, humidity, lighting and diet beside them where Merck covers the species. Search for your animal, or filter by group or UVB zone.

Reptile temperatures, UVB zones and humidity by species

Species listed

Shade dwellers (zone 1)

Mid-day baskers (zone 4)

With Merck humidity figures

Find a species

Ferguson zones group species by how much UVB they meet in the wild, from zone 1 (shade dwellers) to zone 4 (mid-day baskers). The UV-Tool temperatures are summer figures: basking is the surface temperature under the lamp, day and night are air temperatures. Merck's range is the air temperature gradient across the enclosure.

Showing 59 of 59 species

Bearded dragonPogona vitticeps
Ferguson zone 3–4Lizard
UV-Tool: basking surface 40–45°C (104–113°F), daytime air 25–30°C (77–86°F), night air 20–25°C (68–77°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11 to 14:10
Winter treatment
Cooling or Brumation
Merck: preferred air temperature range
25–32°C (77–90°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
20–30%
Merck: lighting
UVB essential
Merck: diet
Mainly insectivorous; partly carnivorous and herbivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table; Our setup guide
Leopard geckoEublepharis macularius
Ferguson zone 1LizardSources differ on UVB
UV-Tool: basking surface 32°C (90°F), daytime air 25–29°C (77–84°F), night air 20–24°C (68–75°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Merck: preferred air temperature range
25–30°C (77–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
20–30%
Merck: lighting
No special lighting required (UVB still recommended)
Merck: diet
Mainly insectivorous; partly carnivorous
The UV-Tool puts this species in zone 1, so it suggests low-level UVB. Merck lists no special lighting requirement but adds that UVB is still recommended for its likely health benefits.
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table; Our setup guide
Crested geckoCorrelophus (Rhacodactylus) ciliatus
Ferguson zone 1Lizard
UV-Tool: basking surface 28°C (82°F), daytime air 25–28°C (77–82°F), night air 23–25°C (73–77°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix; Our setup guide
Gargoyle geckoRhacodactylus auriculatus
Ferguson zone 2Lizard
UV-Tool: basking surface 29°C (84°F), daytime air 25–29°C (77–84°F), night air 20–25°C (68–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Giant day geckoPhelsuma grandis
Ferguson zone 3Lizard
UV-Tool: basking surface 30–35°C (86–95°F), daytime air 25–30°C (77–86°F), night air 23–25°C (73–77°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
13:11
Source: Baines et al. 2016, UV-Tool appendix
Electric blue day geckoLygodactylus williamsi
Ferguson zone 2–3Lizard
UV-Tool: basking surface 30–32°C (86–90°F), daytime air 26–28°C (79–82°F), night air 20–22°C (68–72°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Henkel's leaf-tailed geckoUroplatus henkeli
Ferguson zone 1–2Lizard
UV-Tool: basking surface 25–28°C (77–82°F), daytime air 23–25°C (73–77°F), night air 18–20°C (64–68°F). Zone 1–2 (crepuscular or shade dweller to partial sun or occasional basker) means a UV index gradient of about 0 to 1, peaking at 0.6 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Eastern blue-tongued skinkTiliqua scincoides
Ferguson zone 2–3Lizard
UV-Tool: basking surface 35–45°C (95–113°F), daytime air 28–32°C (82–90°F), night air 20–24°C (68–75°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
13:11 to 14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix; Our setup guide
Blotched blue-tongued skinkTiliqua nigrolutea
Ferguson zone 2–3Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 26–30°C (79–86°F), night air 18–22°C (64–72°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling or Brumation
Source: Baines et al. 2016, UV-Tool appendix; Our setup guide
Solomon Islands skink (monkey-tailed skink)Corucia zebrata
Ferguson zone 2Lizard
UV-Tool: basking surface 30–35°C (86–95°F), daytime air 27–29°C (81–84°F), night air 23–25°C (73–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Red-eyed crocodile skinkTribolonotus gracilis
Ferguson zone 1Lizard
UV-Tool: basking surface 28–32°C (82–90°F), daytime air 23–28°C (73–82°F), night air 23–25°C (73–77°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Fire skinkLepidothyris (Riopa) fernandi
Ferguson zone 2Lizard
UV-Tool: basking surface 35°C (95°F), daytime air 25–30°C (77–86°F), night air 20–25°C (68–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Cunningham's skinkEgernia cunninghami
Ferguson zone 3–4Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 28–32°C (82–90°F), night air 20–24°C (68–75°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling or Brumation
Source: Baines et al. 2016, UV-Tool appendix
Veiled chameleonChamaeleo calyptratus
Ferguson zone 3Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 25–35°C (77–95°F), night air 23–25°C (73–77°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
13:11
Source: Baines et al. 2016, UV-Tool appendix
Panther chameleonFurcifer pardalis
Ferguson zone 3Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 25–30°C (77–86°F), night air 18–24°C (64–75°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12 to 13:11
Source: Baines et al. 2016, UV-Tool appendix
Jackson's chameleonTrioceros jacksonii
Ferguson zone 2–3Lizard
UV-Tool: basking surface 36°C (97°F), daytime air 24–25°C (75–77°F), night air 16–17°C (61–63°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Green anoleAnolis carolinensis
Ferguson zone 2Lizard
UV-Tool: basking surface 30–35°C (86–95°F), daytime air 25–30°C (77–86°F), night air 20–25°C (68–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Chinese water dragonPhysignathus cocincinus
Ferguson zone 2–3Lizard
UV-Tool: basking surface 30–40°C (86–104°F), daytime air 26–28°C (79–82°F), night air 20–22°C (68–72°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Cooling
Merck: preferred air temperature range
24–30°C (75–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
80–90%
Merck: lighting
UVB essential
Merck: diet
Mainly insectivorous; partly carnivorous and herbivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Australian water dragonIntellagama lesueurii
Ferguson zone 2Lizard
UV-Tool: basking surface 35°C (95°F), daytime air 25–30°C (77–86°F), night air 20–25°C (68–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Brumation
Source: Baines et al. 2016, UV-Tool appendix
Green basiliskBasiliscus plumifrons
Ferguson zone 2Lizard
UV-Tool: basking surface 30–35°C (86–95°F), daytime air 25–30°C (77–86°F), night air 24–26°C (75–79°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Savannah monitorVaranus exanthematicus
Ferguson zone 3–4Lizard
UV-Tool: basking surface 55–65°C (131–149°F), daytime air 30–40°C (86–104°F), night air 23°C (73°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Cooling
Merck: preferred air temperature range
25–32°C (77–90°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
20–40%
Merck: lighting
UVB essential
Merck: diet
Mainly carnivorous; partly insectivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Emerald tree monitorVaranus prasinus
Ferguson zone 2Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 28–32°C (82–90°F), night air 24–26°C (75–79°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Black tree monitorVaranus beccarii
Ferguson zone 3Lizard
UV-Tool: basking surface 40–50°C (104–122°F), daytime air 28–35°C (82–95°F), night air 23–26°C (73–79°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Argentine black and white teguSalvator (Tupinambis) merianae
Ferguson zone 3Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 25–30°C (77–86°F), night air 20°C (68°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Brumation
Source: Baines et al. 2016, UV-Tool appendix
Egyptian uromastyxUromastyx aegyptia
Ferguson zone 4Lizard
UV-Tool: basking surface 45–50°C (113–122°F), daytime air 30–38°C (86–100°F), night air 20–25°C (68–77°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Ornate uromastyxUromastyx ornata
Ferguson zone 4Lizard
UV-Tool: basking surface 40–50°C (104–122°F), daytime air 30°C (86°F), night air 20°C (68°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Saharan uromastyxUromastyx geyri
Ferguson zone 4Lizard
UV-Tool: basking surface 45–50°C (113–122°F), daytime air 28–35°C (82–95°F), night air 16–18°C (61–64°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
12:12
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Collared lizardCrotaphytus collaris
Ferguson zone 3–4Lizard
UV-Tool: basking surface 40–48°C (104–118°F), daytime air 25–32°C (77–90°F), night air 20–26°C (68–79°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Brumation or Hibernation
Source: Baines et al. 2016, UV-Tool appendix
Blue spiny lizardSceloporus serrifer cyanogenys
Ferguson zone 4Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 28–35°C (82–95°F), night air 24–26°C (75–79°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Source: Baines et al. 2016, UV-Tool appendix
Sudan plated lizardGerrhosaurus major
Ferguson zone 3Lizard
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 25–30°C (77–86°F), night air 20°C (68°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12 to 13:11
Winter treatment
None or Cooling
Source: Baines et al. 2016, UV-Tool appendix
Rhinoceros iguanaCyclura cornuta
Ferguson zone 4Lizard
UV-Tool: basking surface 40–50°C (104–122°F), daytime air 30–35°C (86–95°F), night air 25–28°C (77–82°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11
Source: Baines et al. 2016, UV-Tool appendix
Corn snakePantherophis guttatus
Ferguson zone 1–2SnakeSources differ on UVB
UV-Tool: basking surface 31°C (88°F), daytime air 24–26°C (75–79°F), night air 20°C (68°F). Zone 1–2 (crepuscular or shade dweller to partial sun or occasional basker) means a UV index gradient of about 0 to 1, peaking at 0.6 to 3 at the basking spot.
Day length (light:dark hours)
13:11
Merck: preferred air temperature range
25–30°C (77–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
30–70%
Merck: lighting
No special lighting required (UVB still recommended)
Merck: diet
Mainly carnivorous
The UV-Tool puts this species in zone 1–2, so it suggests low-level UVB. Merck lists no special lighting requirement but adds that UVB is still recommended for its likely health benefits.
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table; Our setup guide
Ball pythonPython regius
Ferguson zone 2SnakeSources differ on UVB
UV-Tool: basking surface 35–40°C (95–104°F), daytime air 28–30°C (82–86°F), night air 24–26°C (75–79°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Winter treatment
Cooling
Merck: preferred air temperature range
25–30°C (77–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
50–80%
Merck: lighting
No special lighting required (UVB still recommended)
Merck: diet
Mainly carnivorous
The UV-Tool puts this species in zone 2, so it suggests low-level UVB. Merck lists no special lighting requirement but adds that UVB is still recommended for its likely health benefits.
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table; Our setup guide
Boa constrictorBoa constrictor
Ferguson zone 2SnakeSources differ on UVB
UV-Tool: basking surface 28–30°C (82–86°F), daytime air 24–30°C (75–86°F), night air 18–24°C (64–75°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Cooling
Merck: preferred air temperature range
28–31°C (82–88°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
70–95%
Merck: lighting
No special lighting required (UVB still recommended)
Merck: diet
Mainly carnivorous
The UV-Tool puts this species in zone 2, so it suggests low-level UVB. Merck lists no special lighting requirement but adds that UVB is still recommended for its likely health benefits.
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Western hognose snakeHeterodon nasicus
Ferguson zone 2Snake
UV-Tool: basking surface 28–30°C (82–86°F), daytime air 24–30°C (75–86°F), night air 20–24°C (68–75°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling or Brumation
Source: Baines et al. 2016, UV-Tool appendix
Pueblan milk snakeLampropeltis triangulum campbelli
Ferguson zone 1Snake
UV-Tool: basking surface 28–32°C (82–90°F), daytime air 24–28°C (75–82°F), night air 24–26°C (75–79°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Brumation
Source: Baines et al. 2016, UV-Tool appendix
Sinaloan milk snakeLampropeltis triangulum sinaloae
Ferguson zone 1Snake
UV-Tool: basking surface 28–32°C (82–90°F), daytime air 24–28°C (75–82°F), night air 24–26°C (75–79°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Brumation
Source: Baines et al. 2016, UV-Tool appendix
Bredl's carpet pythonMorelia bredli
Ferguson zone 2Snake
UV-Tool: basking surface 30–32°C (86–90°F), daytime air 28–30°C (82–86°F), night air 26–28°C (79–82°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
13:11 to 14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Diamond pythonMorelia spilota spilota
Ferguson zone 3Snake
UV-Tool: basking surface 32°C (90°F), daytime air 25–28°C (77–82°F), night air 20–26°C (68–79°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Green tree pythonMorelia viridis
Ferguson zone 1Snake
UV-Tool: daytime air 26–30°C (79–86°F), night air 24–26°C (75–79°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Emerald tree boaCorallus caninus
Ferguson zone 1Snake
UV-Tool: daytime air 26–30°C (79–86°F), night air 24–26°C (75–79°F). Zone 1 (crepuscular or shade dweller) means a UV index gradient of about 0 to 0.7, peaking at 0.6 to 1.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Dumeril's boaAcrantophis dumerili
Ferguson zone 2Snake
UV-Tool: basking surface 40–45°C (104–113°F), daytime air 30–35°C (86–95°F), night air 24–28°C (75–82°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Children's pythonAntaresia childreni
Ferguson zone 1–2Snake
UV-Tool: basking surface 40–45°C (104–113°F), daytime air 28–35°C (82–95°F), night air 25–28°C (77–82°F). Zone 1–2 (crepuscular or shade dweller to partial sun or occasional basker) means a UV index gradient of about 0 to 1, peaking at 0.6 to 3 at the basking spot.
Day length (light:dark hours)
12:12 to 13:11
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Woma pythonAspidites ramsayi
Ferguson zone 1–2Snake
UV-Tool: basking surface 32°C (90°F), daytime air 28–30°C (82–86°F), night air 25–28°C (77–82°F). Zone 1–2 (crepuscular or shade dweller to partial sun or occasional basker) means a UV index gradient of about 0 to 1, peaking at 0.6 to 3 at the basking spot.
Day length (light:dark hours)
13:11 to 14:10
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Sulcata tortoiseCentrochelys sulcata
Ferguson zone 3–4Tortoise
UV-Tool: basking surface 45–50°C (113–122°F), daytime air 30–35°C (86–95°F), night air 25–28°C (77–82°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11
Source: Baines et al. 2016, UV-Tool appendix
Leopard tortoiseStigmochelys (Geochelone) pardalis
Ferguson zone 3Tortoise
UV-Tool: basking surface 40–50°C (104–122°F), daytime air 28–32°C (82–90°F), night air 24–28°C (75–82°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Cooling
Merck: preferred air temperature range
25–30°C (77–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
30–50%
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous; partly carnivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Red-footed tortoiseChelonoidis (Geochelone) carbonaria
Ferguson zone 1–2Tortoise
UV-Tool: basking surface 30–35°C (86–95°F), daytime air 27–30°C (81–86°F), night air 24–26°C (75–79°F). Zone 1–2 (crepuscular or shade dweller to partial sun or occasional basker) means a UV index gradient of about 0 to 1, peaking at 0.6 to 3 at the basking spot.
Day length (light:dark hours)
13:11
Merck: preferred air temperature range
25–30°C (77–86°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
50–90%
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous; partly carnivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Yellow-footed tortoiseChelonoidis denticulata
Ferguson zone 2Tortoise
UV-Tool: basking surface 28–32°C (82–90°F), daytime air 25–28°C (77–82°F), night air 22°C (72°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
12:12
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Russian tortoiseTestudo (Agrionemys) horsfieldii
Ferguson zone 3Tortoise
UV-Tool: basking surface 35°C (95°F), daytime air 25–30°C (77–86°F), night air 20°C (68°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Hibernation
Source: Baines et al. 2016, UV-Tool appendix
Hermann's tortoiseTestudo hermanni
Ferguson zone 3Tortoise
UV-Tool: basking surface 35°C (95°F), daytime air 22–26°C (72–79°F), night air 10–15°C (50–59°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Hibernation
Source: Baines et al. 2016, UV-Tool appendix
Greek (spur-thighed) tortoiseTestudo graeca
Ferguson zone 3Tortoise
UV-Tool: basking surface 35°C (95°F), daytime air 20–30°C (68–86°F), night air 10–15°C (50–59°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Hibernation
Merck: preferred air temperature range
20–28°C (68–82°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
30–50%
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous; partly carnivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Marginated tortoiseTestudo marginata
Ferguson zone 4Tortoise
UV-Tool: basking surface 35°C (95°F), daytime air 28–32°C (82–90°F), night air 20–24°C (68–75°F). Zone 4 (mid-day sun basker) means a UV index gradient of about 2.6 to 3.5, peaking at 4.5 to 9.5 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Brumation
Source: Baines et al. 2016, UV-Tool appendix
Indian star tortoiseGeochelone elegans
Ferguson zone 3Tortoise
UV-Tool: basking surface 30°C (86°F), daytime air 20–25°C (68–77°F), night air 20–25°C (68–77°F). Zone 3 (open or partial sun basker) means a UV index gradient of about 1 to 2.6, peaking at 2.9 to 7.4 at the basking spot.
Day length (light:dark hours)
12:12
Source: Baines et al. 2016, UV-Tool appendix
Elongated tortoiseIndotestudo elongata
Ferguson zone 2Tortoise
UV-Tool: basking surface 35–45°C (95–113°F), daytime air 24–30°C (75–86°F), night air 20–25°C (68–77°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Cooling
Source: Baines et al. 2016, UV-Tool appendix
Eastern box turtleTerrapene carolina
Ferguson zone 2Turtle
UV-Tool: basking surface 35°C (95°F), daytime air 22–30°C (72–86°F). Zone 2 (partial sun or occasional basker) means a UV index gradient of about 0.7 to 1, peaking at 1.1 to 3 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Hibernation
Merck: preferred air temperature range
22–28°C (72–82°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
50–80%
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous and insectivorous; partly carnivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Red-eared sliderTrachemys scripta elegans
Ferguson zone 3–4Turtle
UV-Tool: basking surface 35°C (95°F), daytime air 25–30°C (77–86°F), night air 22°C (72°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11
Winter treatment
Hibernation
Merck: preferred air temperature range
22–27°C (72–81°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
Aquatic species
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous and insectivorous; partly carnivorous
Source: Baines et al. 2016, UV-Tool appendix; Merck Veterinary Manual table
Yellow-bellied sliderTrachemys scripta scripta
Ferguson zone 3–4Turtle
UV-Tool: basking surface 35°C (95°F), daytime air 25–30°C (77–86°F). Zone 3–4 (open or partial sun basker to mid-day sun basker) means a UV index gradient of about 1 to 3.5, peaking at 2.9 to 9.5 at the basking spot.
Day length (light:dark hours)
13:11 to 14:10
Winter treatment
Hibernation
Source: Baines et al. 2016, UV-Tool appendix
Common musk turtleSternotherus odoratus
Ferguson zone 2–3Turtle
UV-Tool: basking surface 35°C (95°F), daytime air 22–30°C (72–86°F). Zone 2–3 (partial sun or occasional basker to open or partial sun basker) means a UV index gradient of about 0.7 to 2.6, peaking at 1.1 to 7.4 at the basking spot.
Day length (light:dark hours)
14:10
Winter treatment
Hibernation
Source: Baines et al. 2016, UV-Tool appendix
Green iguanaIguana iguana
Not in the UV-ToolLizard
Merck lists a preferred air temperature range of 29–33°C (84–91°F) and humidity of 60–85%.
Merck: preferred air temperature range
29–33°C (84–91°F); basking about 5°C warmer, nights about 5°C cooler
Merck: humidity
60–85%
Merck: lighting
UVB essential
Merck: diet
Mainly herbivorous
Source: Merck Veterinary Manual table

Sources: Baines F. et al. (2016), "How much UV-B does my reptile need? The UV-Tool", Journal of Zoo and Aquarium Research 4(1): 42–63, appendix; and the Merck Veterinary Manual table "Important Husbandry Requirements for Selected Reptiles". Read October 2026. Winter cooling and hibernation temperatures are in the UV-Tool appendix. Ask a reptile vet before changing a setup for an animal that is unwell.

How to read the chart

Basking surface is the temperature of the surface the animal lies on under the heat lamp, measured with an infrared thermometer, not the air.
Day and night are air temperatures. Give a gradient: the cool end of the enclosure should sit near the low end of the day range.
Ferguson zone groups species by the UVB they meet in the wild. Each zone comes with a UV index range for the enclosure and a higher maximum at the basking spot, which the chart spells out for each species.
Merck's range is the air temperature gradient a species prefers. Merck notes that basking spots should run about 5°C warmer and nights about 5°C cooler.

Ferguson zone	Behaviour	Average UV index	Maximum at basking spot
1	Crepuscular or shade dweller	0 to 0.7	0.6 to 1.4
2	Partial sun or occasional basker	0.7 to 1.0	1.1 to 3.0
3	Open or partial sun basker	1.0 to 2.6	2.9 to 7.4
4	Mid-day sun basker	2.6 to 3.5	4.5 to 9.5

Of the 59 species, 12 include zone 1 and 13 include zone 4. The hottest basking spots belong to desert baskers: savannah monitors at 55 to 65°C, and Egyptian and Saharan uromastyx and sulcata tortoises at 45 to 50°C. For lamps that reach each zone, see UVB and Ferguson zones explained and the best UVB lights.

Where the sources disagree

Care sheets rarely agree to the degree, and this chart shows where its two sources part ways:

UVB for snakes and leopard geckos. Merck lists no special lighting requirement for ball pythons, boa constrictors, corn snakes and leopard geckos, while adding that UVB is still recommended. The UV-Tool puts all four in zones 1 to 2, which means low-level UVB. These four carry a "Sources differ on UVB" label in the chart.
Temperatures. Merck gives one air temperature range per species; the UV-Tool splits basking, day and night. For a ball python, Merck's 25 to 30°C range and the UV-Tool's 28 to 30°C day figure overlap at the warm end.
Bearded dragons. The UV-Tool's 40 to 45°C basking figure is a little hotter than the RSPCA's 38 to 42°C used in our bearded dragon setup guide. Both are in published care guidance; start within the overlap and watch the animal.

Whatever figures you aim for, run every heat source through a thermostat and measure the basking surface; see the best reptile thermostats and our heating safety guide.

Data and updates

Species figures are the summer values from the appendix of Baines et al. (2016); winter cooling, brumation and hibernation temperatures are in the same appendix. Merck figures come from its table of husbandry requirements for selected reptiles. Both were read in October 2026, and scientific names are updated where the genus has changed since 2016. Individual animals vary: a reptile vet can advise on a sick or elderly animal.

Frequently asked questions

What temperature does a bearded dragon need?

The UV-Tool lists a basking surface of 40 to 45°C (104 to 113°F), daytime air of 25 to 30°C (77 to 86°F) and night air of 20 to 25°C (68 to 77°F). Merck gives an air temperature range of 25 to 32°C with humidity of 20 to 30%. Bearded dragons are Ferguson zone 3 to 4, so they need strong UVB.

Do snakes need UVB?

The UV-Tool assigns common pet snakes to the lower zones: corn snakes zone 1 to 2, ball pythons and boa constrictors zone 2, which means low-level UVB. Merck lists no special lighting requirement for these snakes but says UVB is still recommended for its likely health benefits.

What is a Ferguson zone?

A grouping of reptiles by the ultraviolet light they meet in the wild, from zone 1 (shade dwellers, average UV index 0 to 0.7) to zone 4 (mid-day sun baskers, 2.6 to 3.5). Keepers use it to choose a UVB lamp and its distance from the basking spot.

How warm should a reptile enclosure be at night?

It depends on the species. In the UV-Tool, leopard geckos drop to 20 to 24°C at night, ball pythons to 24 to 26°C, and bearded dragons to 20 to 25°C. Merck's general rule is that nights can fall about 5°C below the daytime range.

What humidity do reptiles need?

Merck lists 20 to 30% for bearded dragons and leopard geckos, 50 to 80% for ball pythons, 70 to 95% for boa constrictors and 80 to 90% for water dragons, and notes that humidity needs rise during shedding. The UV-Tool does not give humidity.

Sources

How much UV-B does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity (Baines et al. 2016), Journal of Zoo and Aquarium Research
Important Husbandry Requirements for Selected Reptiles, Merck Veterinary Manual
Reptile Housing Requirements, MSD Veterinary Manual

Cover photo: bartagame, central bearded dragon, dragón barbudo central, streifenköpfige bartagame by Max Tibby, CC0 1.0, via inaturalist. Cropped.

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Heat & UVBTemperatureUVB Ferguson Zones HumidityCare

Heat & UVBOct 9, 202611 min

Reptile Temperature and UVB Chart: Basking, Day and Night Temps for 59 Species

Reptile temperatures, UVB zones and humidity by species

How to read the chart

Where the sources disagree

Data and updates

Frequently asked questions

What temperature does a bearded dragon need?

Do snakes need UVB?

What is a Ferguson zone?

How warm should a reptile enclosure be at night?

What humidity do reptiles need?

Sources

Best Reptile Heat Lamps of 2026: Halogen, Deep Heat and Ceramic

Best Reptile Heat Mats of 2026: Under Tank Heaters Compared

Best Reptile Thermometers and Hygrometers of 2026

Reptile temperatures, UVB zones and humidity by species

How to read the chart

Where the sources disagree

Data and updates

Frequently asked questions

What temperature does a bearded dragon need?

Do snakes need UVB?

What is a Ferguson zone?

How warm should a reptile enclosure be at night?

What humidity do reptiles need?

Sources

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Best Reptile Heat Lamps of 2026: Halogen, Deep Heat and Ceramic

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