Well, you will know if the snake likes it warmer. If the snake is ALWAYS on the warm side, then the cool side is a little too cool. But from my experience, i find most snakes that people say are 'tropical' seem to actually like it around 80F. At least all my snakes do. Like i said, i very rarely see them on the warm side on the flexwatt unless they are shedding, otherwise they spend a good portion of their time on the 77-80F cool side.