Why does my central unit quit working at night?

works well from 10:00 am to midnight but then it cuts off & doesn't cut back on until the next morning around 10:00. Outside unit quits the inside blower continues. Works very well in hot daylight hours. I checked the pan & pan switch. Changed filter which I do often. It will freeze you out in the day, but quits every night in the middle of the night. HELP!?