Temp gauge rising

Its about 30 degrees out and i noticed for a few weeks that when my lumina sits after driving it..........the temp gauge starts to rise past half way.........then i start driving it again and it goes back down........it rises very quickly too.........it has never had this problem before even in the summer time...........it's now much colder .............any ideas on where to look.???????? could this be as simple as the fans not running.........i noticed they were not turning when i looked under the hood?

Sounds like your thermostat is sticking. While you are sitting there there isn't much pressure because the wated pump isn't spining very fast, but when you hit the gas the water pump starts spinning faster and puts pressure on the thermostat and opens it. I would check that first.

well offroad is probably right on the thermostat, as for the fans they are electric and kick on and off with temp rise, i would run the car for awile and see if they turn on at all, not hard to fix if they wont kick on you can hook them up to run all the time<ghetto fix> or have the fan motor checked or even the sensor that runs it