Well, you'll get different answers from different people depending on their personal experience. The temperatures of the part of the world where they come from will not vary much over the course of a year. The temperature typically varies from 74°F to 91°F and is rarely below 70°F or above 94°F. I personally try to keep my hot spot temps under 90 degrees, generally somewhere between 86-90 and I've had good luck with it.