Leopard gecko temperature is not one number — it's a gradient with a floor, an air layer, and a cool escape hatch. Most heating problems in this species come from a setup that hits one target and misses the other three. This guide gives you the exact numbers, the heat sources that produce them, and the measurement routine that tells you whether your tank is actually working.
The Four Numbers to Build Around
Everything else in this article is downstream of this table. Print it, tape it inside the stand.
| Zone | Target (°F) | Target (°C) | How to measure it |
|---|---|---|---|
| Warm hide floor (belly heat) | 88–92°F | 31–33°C | Infrared temp gun, pointed at the substrate or tile inside the warm hide |
| Warm side ambient air | 80–84°F | 27–29°C | Digital probe thermometer, 2 inches above the floor, warm end |
| Cool side | 70–77°F | 21–25°C | Digital probe thermometer, cool end, same height |
| Night, whole enclosure | Low 70s°F, floor 65°F (18°C) | 21–24°C | Same probes, read 1 hour after lights out |
The floor number matters most. A leopard gecko's belly sits on the surface, not in the air two feet above it. If your warm hide floor reads 83°F, you have a cool tank no matter what your wall thermometer says.
The air numbers exist to give the animal a choice. A gradient spanning roughly 20°F from warm hide to cool corner lets the gecko do its own thermoregulation — move to the warm floor after eating, shift to the cool end when it's done. You are not setting a temperature. You are setting a menu.
Why a Heat Mat Alone Is a Half-Answer
For about twenty years, the standard advice was "under-tank heater, done." That advice wasn't wrong, it was incomplete.
Leopard geckos are crepuscular — active at dawn and dusk — and in the wild they live in arid grasslands and rocky desert across Pakistan, Afghanistan, and western India (see the Animal Diversity Web account). They spend the hot middle of the day in burrows, then emerge to press themselves against rocks that have been baking in the sun. That behavior is called cryptic basking, and it tells you two things: they want contact heat, and they want radiant heat from above.
An under-tank heat mat delivers the first and none of the second. It warms glass, which warms substrate, which warms a belly — no air, no visible light, nothing for the gecko to orient toward. That still makes it the most practical way to guarantee belly heat overnight, but it is one component, not the system.
The overhead half does the rest. A halogen or incandescent basking bulb produces infrared-A and infrared-B, which penetrate tissue more deeply than the infrared-C a mat puts out, and it builds a bright, defined warm zone where a crepuscular lizard will choose to sit at dusk.
Heat Sources Compared
| Heat source | What it actually heats | Day / night | Thermostat type | Where it fits |
|---|---|---|---|---|
| Under-tank heat mat | Floor contact patch only | Either; best as 24/7 belly heat | On/off or pulse proportional | Standard on glass tanks with thin substrate |
| Halogen flood bulb | Air, surfaces, deep radiant heat + light | Day only | Dimming | Best daytime gradient and basking zone |
| Deep heat projector (DHP) | Radiant heat, no visible light | Day or night | Dimming | Lightless setups, night heat, PVC enclosures |
| Ceramic heat emitter (CHE) | Radiant heat, no light, dries air fast | Night | On/off or pulse proportional | Backup night heat in cold rooms |
| Heat rock | Uneven contact points | Never | None that helps | Do not use |
Two practical notes that save people a return shipment:
Wattage is a guess until you measure it. A 50-watt halogen is roughly right over a 20-gallon long, 75 watts for a 40-gallon breeder, and 100–150 watts for a 48×24-inch footprint. Mount the fixture 12–18 inches above the basking surface and then check the floor with a temp gun. Room temperature moves these numbers by 10°F or more, so the same bulb can be correct in July and useless in January.
Never put a heat mat under a PVC or wooden enclosure. It traps heat against a material that warps or chars. Mats belong under glass. Overhead heat is the only option for PVC and wood.
Thermostats Are Not Accessories
An unregulated heat mat can reach 120°F+ (49°C) on the glass. That is hot enough to cause full-thickness burns on a gecko's underside, and it happens in setups where the keeper "checked it and it felt fine." Every heat source in the enclosure gets a thermostat. No exceptions, including the cheap 8-watt mat.
Match the thermostat to the source:
- Light-emitting bulbs (halogen, incandescent): dimming thermostat. On/off cycling makes the bulb flicker visibly, which stresses the animal and kills bulbs early.
- Heat mats, CHEs, DHPs: on/off is acceptable and cheaper; pulse proportional holds a steadier temperature if you want to pay for it.
Set the thermostat to 90°F (32°C) for a warm hide target of 88–92°F, then stop touching the dial. Daily nudging is how a mat ends up running near-continuous.
Building the Gradient, Step by Step
1. Size for length, not volume. A 40-gallon breeder (36×18×18 inches) is the practical minimum for an adult; a 4×2×2-foot front-opening enclosure is better and is where most experienced keepers end up. You cannot build a 20°F gradient across 24 inches of floor. Length is the feature you're buying.
2. Choose the warm end and commit. Pick one side — left or right, doesn't matter — and put every heat source there. A mat centered in the tank produces two lukewarm ends and no gradient.
3. Place the heat sources.
- Heat mat: outside, stuck to the bottom glass, covering about one-third of the floor, directly under the warm hide. If the enclosure sits on foam or wood, raise it on small feet so trapped heat doesn't cook the mat.
- Basking bulb: in a dome fixture over the warm end, roughly 3 inches in from the side wall, 12–18 inches above the basking surface. Use a guard if the gecko can climb within reach.
4. Put the thermostat probe on the floor of the warm hide. Flat on the substrate or tile, where the gecko's belly rests, taped down with a small piece of electrical tape. Not on the glass underneath. Not clipped to the back wall. Not dangling.
5. Keep the substrate over the mat thin. An inch of loose substrate or a slate tile is right. Two inches of coco fiber over a mat insulates it from the animal and gives you a floor that reads 78°F while the thermostat reads 90°F.
6. Put the lights on a timer. 10–12 hours on, 12–14 hours off. A fixed photoperiod does as much for appetite and shedding as the temperature itself, and a timer costs less than one skipped feeding.
7. Measure after two hours, then weekly. Glass, tile, and substrate take time to reach equilibrium. After the initial check, spot-check weekly and any time the season changes.
Measuring: Where Most Setups Go Wrong
A thermostat set to 90°F does not mean the floor is 90°F. It means the probe is 90°F. Probe placement decides whether those are the same thing.
| Where the probe sits | What it typically reads | What it means | Fix |
|---|---|---|---|
| Flat on the warm hide floor | 88–92°F | Correct | Leave it alone |
| Taped to the glass under the tank | 95°F+ | Reading the hottest strip, not the resting surface | Move it inside, on top of the substrate |
| Clipped to the wall, mid-air | 60s–70s°F | Reading air; the mat runs nonstop trying to hit target | Tape the tip flat to the floor |
| Buried under 2 inches of substrate | Low, erratic | Insulation is blocking heat transfer | Thin the substrate over the mat |
| Loose under the hide | Swings wildly | Bad contact | Re-tape and re-check weekly |
Two tools cover the job: a digital thermometer with two remote probes, one per zone, and an infrared temp gun for surfaces. The gun will not read ambient air, and pointing it at glass gives you the glass rather than the floor beneath — aim at the substrate and the top of the hide.
Read at three moments: mid-afternoon, one hour after lights out, and just before lights on. Those readings tell you whether the night drop happens at all.
Nighttime Heat: When You Actually Need It
Most homes run 65–75°F at night, and that's fine. A 10–15°F drop is normal and part of the animal's rhythm; a tank that never cools never signals a day cycle.
The intervention point is a room that drops below 65°F (18°C). At that point the gecko's digestion slows and immune function with it. Add heat with a lightless source on its own thermostat:
- Deep heat projector or ceramic heat emitter over the warm end, set to hold a 70–72°F floor.
- Keep it on a separate thermostat from the daytime bulb so the two don't fight each other.
Skip the colored night bulbs — red, blue, and "moonlight" versions. The old claim that reptiles can't see those wavelengths doesn't hold up, and light at night disrupts sleep in a species that is already most active at dusk.
Common Mistakes That Cause Real Problems
- No thermostat. The single most common cause of thermal burns, and entirely preventable for the price of a controller.
- Probe in the air. Your mat runs continuously, the floor overshoots, and the gecko stops using the warm hide.
- A mat spanning the whole floor. No cool end means no thermoregulation; chronic stress and poor feeding follow.
- A heat rock. Uneven internal elements and unreliable built-in controls. Contact surfaces can run far hotter than the sensor reads. There is no safe configuration.
- Colored night bulbs. Light at night, every night, for months.
- Thick substrate over the mat. The floor never reaches target and the keeper compensates by cranking the thermostat.
- The wrong tank for the bulb. A 20-gallon long can hold a juvenile but not a 20°F gradient plus three hides, and 100 watts over that footprint will hit basking temperature while cooking the cool end.
When a Heating Problem Looks Like a Health Problem
A cold leopard gecko and a sick leopard gecko behave similarly: no interest in food, sluggish, spending all day in one hide, losing weight slowly. Before you treat anything, measure. A tank reading 79°F on the warm floor will produce exactly those symptoms in a healthy animal.
If the numbers are correct and the behavior continues, that's a veterinary question, not a husbandry one. Persistent anorexia, regurgitation, drooping jaw or rubbery limbs (possible metabolic bone disease), retained shed around toes, or a firm swelling in the belly all warrant an appointment with an exotic veterinarian — a general-practice vet typically has neither the training nor the equipment for reptiles. The Merck Veterinary Manual's reptile chapters are a useful primer on what those symptoms can mean, but they are not a substitute for an exam. Bring your numbers with you.
Heat and UVB: The Overlap People Skip
Heating and lighting get discussed separately, which is why so many setups end up with good temperatures and no vitamin D3 pathway.
Leopard geckos are crepuscular, and for years that was the argument for skipping UVB entirely. The current consensus is softer: low-output UVB is beneficial and low-risk. A 5–7% linear tube (Arcadia ShadeDweller 7% and Zoo Med ReptiSun 5.0 are the two standard options) mounted alongside the basking bulb lets the animal synthesize its own D3 without pushing exposure into bearded-dragon territory.
If you skip UVB, you cannot skip supplementation — calcium with D3 on a proper schedule, every feeding cycle. Both routes work. What fails is doing half of each: no UVB and inconsistent dusting, which is the classic path to MBD.
Budget Tiers: Enough, Good, Do It Once
Typical US retail ranges as of late 2026 for the heating and control side of a leopard gecko setup. Prices move; check current listings before you buy.
| Tier | What's in it | Typical range | Who it's for | Trade-off |
|---|---|---|---|---|
| Enough | 40-gallon breeder tank, 8×12-inch heat mat, on/off thermostat, two-probe digital thermometer | $120–180 | First setup, tight budget, juvenile gecko | Belly heat only; you will add overhead heat later |
| Good | 40-gallon breeder or 4×2×2 PVC, 75W halogen + dimming thermostat, heat mat on the warm hide, IR temp gun | $280–420 | Most adult setups | Two controllers to manage; best heat quality per dollar |
| Do it once | 4×2×2 front-opening PVC, halogen or DHP + dimming thermostat, heat mat, low-output T5 UVB kit, timer, IR gun | $550–850 | Keepers who want one purchase and a decade of use | Upfront cost; oversized for a hatchling |
If you're buying new for an adult, skip "Enough." Not because mat-only fails — thousands of geckos have lived on them — but because you'll buy the halogen, the dimming thermostat, and the temp gun within a year anyway, and the middle purchase is the expensive part.
Whatever you buy, buy the thermometer first. You cannot tune a system you can't read.
Frequently Asked Questions
What temperature should a leopard gecko tank be?
The warm hide floor should sit at 88–92°F (31–33°C), warm-side air at 80–84°F (27–29°C), and the cool side at 70–77°F (21–25°C). At night the whole enclosure can fall into the low 70s, with 65°F (18°C) as the floor you don't want to go below.
Do leopard geckos need a heat lamp or a heat mat?
Both, ideally. The mat guarantees belly heat under the warm hide around the clock; the lamp builds the daytime gradient and the basking zone. A mat-only setup works for a first enclosure, but adding a halogen on a dimming thermostat is the upgrade that changes how the animal behaves.
Do leopard geckos need heat at night?
Usually not. If your room stays above 65°F overnight, let the tank cool — the drop is part of a normal cycle. Below 65°F, add a lightless source (DHP or ceramic heat emitter) on its own thermostat to hold a 70–72°F floor. Never use colored night bulbs.
Where does the thermostat probe go?
Flat on the floor of the warm hide, on top of the substrate or tile, taped down where the gecko's belly rests. Not on the glass underneath the tank, not clipped to the wall, not buried. Air temperature and surface temperature commonly differ by 10°F or more, so a probe in the air regulates nothing useful.
Can I use a heat rock for a leopard gecko?
No. Heat rocks have uneven internal elements and unreliable built-in controls, and the contact surface can run much hotter than the sensor reports. Thermal burns from heat rocks are a routine presentation in exotic practice. A thermostat-controlled mat does the same job safely.
How many hours should the heat lamp stay on?
10–12 hours per day on a timer, with a full dark period overnight. A fixed 12-on/12-off cycle is the simplest and works year-round. If your room gets cold at night, solve that with lightless heat rather than by extending the photoperiod.
The Bottom Line
Build the gradient, then measure it. 88–92°F on the warm hide floor, 70–77°F on the cool side, a controlled drop at night, and a thermostat on every heat source — those four things cover most of what goes wrong with leopard gecko temperature, and none of them require expensive equipment. The temp gun and the probe are the two purchases that make the rest of the setup verifiable.
If you're assembling a tank from scratch, see what's currently in stock at our shop — we stock species by species, so the catalog stays small on purpose. Start with ReptiWise for the husbandry-first side of it, and buy the thermometer before the bulb.