What I see:

I can play the game for many hours at a time without ever seeing a rainstorm, or snow or thunder. I was under the impression that these ought to occur every 2-4 hours of gameplay, on average.

What I expected to see:

The frequency at which it rains should be approximately the same whether you sleep regularly in beds (as I do) or not.

Comments/Explanation/Speculation:

Sleeping in a bed, which I do regularly, appears to reset the weather counter. This is fine by me /when it's raining at the time/, because it's a handy way to turn unwanted weather off in survival mode, but I don't think it should reset the counter if it's /not/ raining at the time, because then you can play for days on end without ever seeing it rain.