Dry overall: 30 to 40 percent
Leopard geckos are the driest-air reptiles on most beginner lists. They come from the rocky grasslands and semi-desert edges of Pakistan, Afghanistan, and northwestern India, and their enclosure air should sit at 30 to 40 percent humidity — roughly the air of an ordinary living room. New keepers who bring a tropical mindset to this species and mist the tank are creating the problem they are trying to avoid: sustained humidity above 50 percent across the whole enclosure is linked with respiratory infections in leopard geckos, which show as lethargy, gaping, and mucus around the nostrils.
The humid hide is the other half of the answer
Dry tank air does not mean a dry gecko. In the wild, a leopard gecko spends its days in a burrow or rock crevice where trapped air and soil moisture keep things far more humid than the surface, and it sheds in that shelter. Copy the arrangement with three hides: a warm hide, a cool hide, and between them in function a humid hide on the warm side — a closed box with one entrance, lined with damp sphagnum moss, moist paper towel, or coconut fibre. Inside that box the humidity runs high enough to loosen a shed; outside it, the tank stays desert-dry. Most shedding trouble in this species traces back to a humid hide that was missing or had dried out.
Reading a shed tells you if the balance is right
A leopard gecko in correct conditions turns pale and ghostly, then sheds and eats the skin within about a day. The places to inspect afterwards are the toes: fine rings of unshed skin collect there when the humid hide is too dry, and over several sheds those rings tighten, cut circulation, and can cost toes — the most common preventable injury in pet leopard geckos. Check the feet after every shed under good light. If skin remains, a shallow lukewarm soak and a gentle cotton-swab roll usually free it; skin that resists should never be pulled.
Water, substrate, and the surfaces to avoid
A small, heavy water dish on the cool side covers drinking without meaningfully raising tank humidity. For substrate, solid surfaces and soil mixes that stay dry on top both work; what matters is that the floor is not kept damp. Spraying regimes, foggers, and large open water features all belong to tropical setups, not this one. A digital hygrometer at floor level on the cool end gives the ambient number that matters, and the humid hide needs no gauge at all — if the moss feels damp when you pinch it, it is doing its job; rewet it a couple of times a week.
Vet signs, and keeping the recipe with the gecko
See a reptile vet for toes that are swollen or dark at the tip, shed that will not come off after soaks, breathing with the mouth open, or a gecko that stops eating and loses tail thickness — by the time a leopard gecko looks obviously unwell, the problem is usually established. The care itself, once understood, is a two-line recipe: dry air, damp hide. Recording exactly that — the ambient range, the hide lining, the rewetting rhythm — in KinsLe Pet Passport means a future keeper does not have to rediscover which half of the rule matters.