I have a 2008 chevy cobalt Lt when I'm driving around town the temperatures go as high as 216F. I don't know what is causing this? Please help me

Could be a few different things. Bad thermostat, the electric cooling fans aren't turning on, air bubble in the cooling system or a bad temp sending unit. Have it looked at by a REPUTABLE mechanic soon or it may cause MAJOR problems to your engine.

TransAm77, sounds like you've been there before. Also Lucia, make sure the fins on the radiator are clear. They usually have a nice butterfly collection this time of year, and that can restrict air flow. Does this rise in temperature happen in town driving in slow moving traffic in hot weather with the air conditioning on? Move to Canada, they have less traffic and less hot days. My first inclination, would be the fluid level, then the fans. If you have a shop look at it, have them also look at the radiator cap.