I have a central air conditioning unit in my home. For about a month now something keeps coming on during hot afternoons that sounds like the blower. The air conditioner is not on (I have checked outside) and the thermostat is not on. But around 1pm-5pm on hot days something is coming on independent of my turning it on. When the temperature outside is mild (Under 80 degrees) this does not happen. Like I said, it sounds like the blower, but I don't feel any air being blown through the vents. I have no idea why this is happening or really what it is. Can anyone help me with this?
Thanks!

It could be a roof attic vent fan. They turn on when the air in the attic gets hot and off when cooled down. Look up on your roof. usually they have a round cover. It could also be a gable vent which does the same thing but you may not be able to see it .