On small ships, it's almost entirely dependent on your job. A lot of times, divisions will hold quarters and other morning meetings topside, almost to force people outside.
I definitely had engineers that never went out except for those mornings. On the other hand, quartermasters and bosun's mates are almost outside, or within view of natural sunlight. If you stand watch on the bridge then you get all the sunlight you can handle for five hours at a time.
Most ships I have seen have "steel beach picnics" pretty much every Sunday afternoon. That's just a bbq back on the flight deck.
The biggest thing driving people outside is the smoke deck. A lot of people smoked because it was an excuse to go stand around outside and hear gossip going around the ship.