My central air was cooling just fine all day. Around 5pm tonight the air coming out of the ducts wasn't cold any longer. I have a computer monitor the temps in the different rooms of the house and I noticed that all the rooms were cool (77-78) until around 5pm when the temps started climbing to 83 or so.

I checked the AC various times and the outside fan is spinning just fine. The air coming through the outside unit is cool instead of hot. The air coming out of the ducts is not cold at all. What would cause this to all of a sudden stop cooling. I can't imagine it would be a freon leak since that should take time. Any clues or suggestions? Could it be some drainiage pipe is clogged?