Leopard Gecko Temperature Guide: Heat Mat Setup and Gradient
Leopard geckos absorb heat through their bellies from warm surfaces — a behavior called thigmothermy. In the wild, they rest on sun-warmed rocks and heated desert soil during dawn and dusk. That’s why your setup uses an under-tank heat mat, not an overhead basking bulb like you’d see for a bearded dragon. The floor temperature at your gecko’s belly level is what matters — not the air temperature six inches above the substrate.
A wrong temperature setup is one of the most common causes of leopard gecko health problems. If the warm side drops below 85°F, food rots in the gut instead of digesting, leading to impaction. If it climbs above 95°F, your gecko stops eating, becomes lethargic, and can suffer thermal burns from an unregulated mat.
Temperature Zones
Your enclosure needs a thermal gradient — one warm end and one cool end. This lets your gecko move between zones to regulate its body temperature. Measure surface temperature (the floor where the gecko’s belly touches), not ambient air temperature.
| Zone | Floor Temperature | What Your Gecko Does Here |
|---|---|---|
| Warm hide | 88–92°F (31–33°C) | Digests food, spends most daylight hours |
| Middle ground | 80–87°F | Moves through when traveling between hides |
| Cool side | 70–75°F (21–24°C) | Sleeps, cools down after a warm meal |
| Nighttime ambient | 65–70°F minimum | Natural rest period — gecko retreats to cool hide |
The warm hide is the most critical zone. Your gecko’s digestive system shuts down below 85°F, and partially digested food sits in the stomach and rots. This causes impaction — one of the leading killers of captive leopard geckos.
The warm hide floor should be a solid, flat surface directly over the heat mat. Bare glass, ceramic tile, or slate transfers heat best. Avoid putting loose substrate directly over the heat mat — not only does it insulate and block heat transfer, but geckos can accidentally ingest it while hunting crickets.
Heat Mat Setup: Step by Step
1. Choose the right mat size
The heat mat covers roughly one-third of the enclosure floor on the warm side only. The cool side gets no heat source.
| Tank size | Mat dimensions | Coverage area |
|---|---|---|
| 10 gallon | 8” × 8” | ~30% of floor |
| 20 gallon long | 11” × 11” | ~30% of floor |
| 30–40 gallon | 11” × 17” | ~30% of floor |
For a standard 20-gallon leopard gecko enclosure the Exo Terra Glass Terrarium is a common choice , the Zoo Med ReptiTherm 10-20 Gal ($25) is the standard fit. It’s an 11” × 11” mat with adhesive backing.
2. Attach the mat
Peel off the backing and stick the mat to the outside bottom of the glass enclosure, centered under the warm hide location. The mat goes on the exterior — never inside the tank where a gecko can reach it. If your enclosure sits on a surface that insulates (wood, foam pad), raise the tank slightly with small feet or spacers so the mat doesn’t overheat from trapped heat.
3. Connect the thermostat — this is non-negotiable
The Inkbird WiFi Heat Mat Thermostat ($36.89) plugs into the heat mat and controls it like a smart switch: on when the floor drops below your set point, off when it hits the target. Without a thermostat, an unregulated mat can reach 120°F+ on the glass surface — hot enough to cause severe burns.
Thermostat probe placement is the single most common setup mistake. The probe must sit flat on the warm hide floor, directly where the gecko’s belly rests. Air temperature and surface temperature can differ by 10°F or more — a probe clipped to the tank wall in mid-air tells you nothing useful.
Tape the probe tip to the glass or tile surface inside the warm hide using a small piece of electrical tape. Set the thermostat to 90°F (the middle of the 88-92°F range). The thermostat will cycle the mat on and off to maintain that floor temperature.
4. Verify with a thermometer
Use the Zoo Med Digital Thermometer ($9.99) — it has two probes. Put one probe on the warm hide floor and the other on the cool side floor. Check both readings. If the warm hide reads 88-92°F and the cool side reads 70-75°F, your gradient is correct.
Wait at least two hours after setup before taking readings. Glass and substrate take time to reach thermal equilibrium.
Never use a heat mat without a thermostat. Unregulated mats can reach 120°F+ on the glass surface, causing severe burns. This is the most dangerous husbandry mistake for leopard geckos — and it’s entirely preventable with a $37 thermostat.
Nighttime Temperatures
At night, all lights off. If your room stays above 65°F, the heat mat thermostat can maintain its daytime 90°F setting — your gecko will simply move to the cool hide if it prefers a lower temperature. Leopard geckos don’t need darkness-specific heat sources in most homes.
If your room regularly drops below 65°F at night (common in winter or air-conditioned spaces), you need a secondary heat source that emits no visible light. A ceramic heat emitter like the LUCKY HERP 150W Ceramic Heat Emitter ($14.39) screwed into a dome fixture above the enclosure works well. Control it with the second outlet on the Inkbird thermostat (it has two independent channels) or a separate on/off thermostat set to 72°F.
Do not use red or purple “night bulbs.” Leopard geckos can see these wavelengths — the light disrupts their crepuscular cycle and stresses them out.
Troubleshooting Temperature Problems
| Symptom | Likely Cause | Fix |
|---|---|---|
| Gecko stays in cool hide, avoids warm side | Warm side surface above 95°F | Check thermostat probe placement; the probe may be in a hot spot. Reduce mat size or thermostat set point. |
| Gecko never leaves warm hide | Cool side below 70°F | Check room temperature. Move the enclosure away from AC vents. If room is cold, add ambient heating or a low-wattage ceramic emitter. |
| Refusing food for 2+ days | Warm hide below 85°F | Verify thermostat probe is on the floor surface, not in the air. Check that the mat is actually turning on (feel the glass under the tank). |
| Stuck shed around toes or tail | Low humidity in the moist hide | This is a humidity problem, not temperature. Add a moist hide on the warm side with damp paper towel (). |
| Gecko pressed flat against glass over mat | Mat too hot, no thermostat, or probe detached | Immediately unplug the mat. Install a thermostat. Check that the probe hasn’t fallen off the floor surface. |
The most common cause of all these problems is a displaced thermostat probe. If the probe falls off the floor and dangles in the air, the thermostat reads a lower temperature and keeps the mat running constantly, overheating the surface. Check probe placement weekly during routine maintenance.
Related Reading
- Leopard Gecko Care Guide — full species overview with all care parameters
- Bearded Dragon Care Guide — compare heat lamp setups (bearded dragons use overhead heat, not belly heat)
- How to Choose a Heat Mat — comparison of mat types, sizes, and brands
- How to Choose a Thermostat — on/off vs. pulse vs. dimming thermostats
- Leopard Gecko Shedding Guide — humidity and moist hide setup for proper sheds
- Leopard Gecko Diet and Feeding — how temperature affects digestion and feeding schedule
- Leopard Gecko UVB Requirements — UVB lighting for shade-dwelling reptiles
- Leopard Gecko Humidity Guide — managing humidity alongside temperature
- How to Set Up a Terrarium — complete enclosure setup guide
- Leopard Gecko Tank Size Guide — how enclosure size affects temperature gradient