How warm does a Leopard gecko's vivarium have to be?

The warm side of the vivarium should be between 87 and 92 degrees Fahrenheit, and the cool side is preferably 80 degrees, but room temperature (about 70-75) should be fine too.

Remember that leopard geckos digest using the heat of the ground, not air temperature, so under the tank heaters (heating pads) are preferable to heat lamps.

Accuracy and consistency are important. They're hardy reptiles, but if kept in an improper or unstable environment, even if they're fine for a few years, will eventually make them sickly. So use a digital thermometer with a probe taped to the hottest spot in the cage to measure, and either use a plug in lamp dimmer or a thermostat to adjust the heat output.