Car "trying" to run hot?

I have a 2001 malibu... It has ran hot twice(several months apart) the gauge tries 2 get to the red area but hasnt since the 2nd time it ran hot... Also when i drive on the freeway it seems to try and go higher but on the service road and residential areas it remains normal... On the freeway It goes up and then goes back down to the half way point... Do u have any idea what this could be or any suggestions??? (thr are no leaks either) i know its not my thermostat