It depends on the deck.

Some observation decks let you hang out all day. Others kick you out after an hour or two. The Empire State Building? No strict time limit — you can stay as long as you want. The Top of the Rock? Same, generally. But a lot of smaller, less touristy decks (like the SkyView in Atlanta or the Space Needle) have a soft limit — they’ll ask you to leave after your timed entry slot closes or if it gets crowded.

Check the fine print when you buy your ticket, or just ask the staff when you arrive. If you’re planning a long photo session or a lazy sunset drink, call ahead. The worst feeling is getting the boot halfway through a good view.

Save yourself the disappointment and just look it up before you go.