I think your temps are fine....IF those are your temps. If she's "freezing cold" when you pick her up from the 80* side of the tank....that tells me it's not really that warm there. What kind of thermometer are you using to measure temps and where exactly is it placed?


IF the temps are what you say they are...and the snake truly has a choice of an optimal range of temps to choose from...then you don't have to "force" it to go to the warm side...it will when it feels like it.

It could also be that you're experiencing a significant drop in temps at night...which would result in her feeling "freezing cold" in the morning. You need to make sure that the 80-90 range stays constant 24/7.