Sounds like you are losing antifreeze. Have you notived steam coming from the tail pipe? Air pockets cause the temp to go up, revving the motor pushes the water pump harder pushing fluid through where the air pocket was....
When was the last time you replaced your water pump?
Notice any leaks from the radiator?
I just replaced my head gasket last weekend. Noticed temp spikes, couldn't keep fluid in the radiator. Cold weather masked the steam ouput in the exhaust initially. Once the engine warmed up it was just enough to expand the gasket and stop the antifreeze from making it to the compression chamber...... I know, not good news, just be aware of the potential problem. Eliminate the simple ones first.....