How a Leopard Gecko Temperature Gradient Actually Works
| Warm hide floor | 88–92°F |
| Cool side | 73–76°F |
| Heated floor coverage | ~1/3 of enclosure |
Why one temperature isn't enough
As an ectotherm, a leopard gecko can't internally regulate its body temperature — it does so behaviorally, by physically moving to a warmer or cooler spot as needed. A gradient gives it that choice; a uniformly heated enclosure doesn't.
Setting it up
Position the heat source (UTH and/or overhead heat) under or over one end only, covering roughly a third of the floor space, leaving the opposite end unheated so it settles naturally at room-adjacent temperature.
Verifying it's actually working
Use a digital probe thermometer at both the warm hide floor and the cool side ambient, not a single stick-on gauge in the middle of the tank, which won't reflect either extreme accurately.
Signs the gradient is off
A gecko permanently stuck in one hide and never exploring, or one that avoids the warm side entirely, often signals the gradient isn't reaching its intended range somewhere.
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A single adult leopard gecko needs a 20-gallon long tank as an absolute minimum, with a 36x18 in (40-gallon breeder) footprint now considered the recommended standard — plus a secure lid, an under-tank heater on a thermostat, a thermal gradient, at least three hides, and a shallow water dish.
Set up in this order: substrate, then heat source wired through a thermostat, then hides and water dish, then decor — and run the whole enclosure for at least 24–48 hours to confirm stable temperatures before your gecko moves in.
Hatchlings can start in a 10-gallon tank or tub, juveniles do well in 20 gallons, and adults need a 20-gallon long as an absolute minimum — with 36x18 in (40-gallon breeder) now the widely recommended standard, not just an upgrade.
Heat a leopard gecko enclosure with an under-tank heater and/or overhead heat source (halogen or deep heat projector) wired through a thermostat — a thermostat is mandatory, not optional, and heat rocks should never be used.
Leopard geckos can survive without UVB using dietary D3 supplementation, but current husbandry guidance now recommends low-level UVB (roughly 2–6% T5) as best practice — it improves D3 synthesis, bone density, and natural behavior, and views on it have shifted significantly from older nocturnal-species advice.
Keep ambient humidity around 30–40% across most of the enclosure, with a dedicated humid hide raised to roughly 70–80% to support smooth, complete sheds.