The cpu temp always goes up when the cpu starts working. At idle, it's always lower. You don't have anything to worry about unless your temps reach 70c or higher under load while gaming. Relax. Your temps are normal. If you live in a hot climate like me, use the a/c once in awhile to cool down your room. That does more good than spending a fortune on the latest cooler.
I know you mean why the variation, the 5 degree climb. It stands to reason some changes occur during sleep including shuting down some system files I suspect.
It leads me to believe either a power function is no longer active in memory or the additional function for wake up is still active and using memory or resources.
You might take a count of total system files open both before and after and see if they match or anything on that line activex etc.