Wind???

when i have my lights off at night should i leave the fan on or turn it off didnt know if it was gettin to hot at night or not

It doesn't hurt to keep the fan on at "night" as long as it is helping keeping the room cool. What size is your fan? Any pictures of your grow room? And also, any recorded temperatures? This will help answer your question, but from what I've seen and read, just keep it on.

Peace
Dirty Kid

If your in flowering stage, make sure the fan doesnt have an indicator light or something. But wind blows at all time of day, so leave it on