Can a drum set be exposed to sunlight?

Sunlight Drum Set

Well, there's hot then there's really hot. Then there's really hot & humid. Heat & humidity will, over time, ruin anything. The problem won't be with the heads themselves (most modern heads are plastic anyway unlike the older cow-skin type). I haven't checked lately but some drum manufacture may also be making the drum itself out of plastic (fiberglass) or some other composite material that would be impervious to the changes heat & humidity would cause. Electric drums come to mind. Also be mindful that humidity may cause inferior metal hardware to rust and if your heads are really tight the added expansion due to the wooden drum swelling can cause the drum head to literally break. If you must put a conventional drum set in that kind of environment be aware that it probably will get grungy looking after a while.

Leaving drums in bright direct sun for long times (days on end) can fade the finish. Extreme heat from sunlight can mess with the tension of the heads. But drums are the toughest instruments on the planet. It takes a lot to really wreck them.

No, they were invented by vampires and direct sunlight will cause them to burst into flame.

I'm kidding.

They'll be fine. As long as they aren't sitting somewhere where the heat will be amplified by the sunlight they'll be okay.