The winter question runs backwards
Most reptile winter advice is about adding heat. The crested gecko, a New Caledonian species that lives in mild, humid forest, flips the problem: he is comfortable at 72–78°F, stressed by sustained heat above the low eighties, and slowed but unharmed by the gentle cool of a normal winter house. He needs no basking lamp in any season. So his winter care starts with a thermometer and a decision — most heated homes need to change nothing at all, and the keeper who adds a heat lamp for winter is the one most likely to cook him.
When a room really is too cold
The threshold that matters is the night, not the afternoon. If his room regularly falls below the mid-sixties while the household sleeps — an unheated spare room, a house kept cold overnight — he will stop eating well, move sluggishly and sit dull and still for long stretches. The fix is modest: move the enclosure into a lived-in room, or add a small heat mat on the side of the glass, run through a thermostat set to take the edge off rather than create a hot spot. Keep him away from radiators and heating vents, which blast hot, dry air in cycles — the worst of both worlds for this species.
Humidity and food in the cool months
Winter's dry indoor air matters more to a crested gecko than winter's temperature. Keep the evening misting that takes humidity up toward 60–80% overnight, with a lighter morning spray and a drier spell during the day so the enclosure cycles rather than staying swampy; constant wet invites mold on food and discomfort on skin. His prepared gecko diet should be offered fresh every other night as usual, though expect slower consumption and some untouched bowls in the coolest weeks — this species simply eats less when it is cooler. A gecko who holds his weight and still fires up at night is fine; the bowl is not the measure, the gecko is.
Signs worth acting on
A cold gecko warms up gradually — never hold a chilled crested gecko against a hot surface or under a lamp; room-temperature patience does it. Treat as vet matters a gecko who loses visible weight, whose hips and tail base thin out, who stops moving at night entirely, or who develops stuck shed gripping the toes, which can cut off circulation. Otherwise, winter for a crested gecko is a quiet season of slightly smaller appetites and longer sleeps in the same foliage he used all summer. Somebody still has to eyeball the thermometer on the coldest nights, and KinsLe Care Teams lets the last person up own that nightly check, marked done with a timestamp.