They know what they're doing. i wouldn't be concerned about it. Mine have daytime highs right now of about 81 degrees. They eat like pigs and grow like weeds. Once summer gets here, they'll really be warming up and they did fine last summer. right from this sites care sheet about Cresties temp requirements. Crested geckos like the same temperature range as most of us prefer, from the high 60's to the low 80's (Fahrenheit). Temperatures above 80 degrees for extended periods of time will stress your gecko and could lead to health problems. For this reason, it is essential not to try to house cresties with species having high heat or basking spot requirements. You can provide a basking spot to your geckos, if you like, by using a low-wattage bulb to create an area in the enclosure that is a few degrees warmer than the ambient temperature, but please check to ensure that in the hottest spot the temperature does not exceed 85 degrees F or so. Crested geckos do require high humidity, but they do not require it on a constant basis. Misting 1-4 times a day (depending on housing and ambient humidity) should be fine, twice a day generally being perfectly adequate.