My car blows hot air for the first few minutes the a/c is on and its stock intake wise... These cars have high underhood temps, so the condenser has to cool all of the hot freon in the system before it gets cold, and theres a fair length of a/c plumbing under hood.

That being said, if it only does it when the car isnt moving it sounds like a fan problem. If it does it all the time you could have a freon problem (low pressure, leak, or something) or the a/c compressor is on its way out. If you have low freon levels and pressures and are still running the a/c the compressor wont be properly lubricated and will prematurely fail