Running your air conditioner at night when the temperature is just a little too warm for you is something we all tend to do to get a goods night's sleep.
Though the right temperature is different for everyone, a few degrees will make all difference. The problem is the shifting in outside temperature through the night in just a few degrees can push the thermostat to shut the compressor off for the rest of the night. And since all windows are shut when the AC is turned on, you will be breathing stale uncooled air for most of the night when the ac cuts out. You will end up with a poor night's sleep or worse, wake up with a headache.
The solution is to leave gaps in your windows. (Minimum 1, or better, 2 windows.) This should not affect the room temperature as much as the temperature difference is not that much.