Not forgetting that most of the time rough weather (without heavy fog of course...) is your best friend. I much prefer attacking a convoy on a moonless night with rough seas than with beautiful and calm weather. Of course when you encounter lonely merchants, the bad thing is that you cannot use the deck gun.
So I would vote for good weather for lonies and rough weather for convoys...:)
In case of heavy fog, well just dive and head south...

Well, I'm not sure about SH3 weather but it's rained at least once every day for 51 days here in Ireland.

But probably not 51 days with gale force winds and heavy fog.

Hey,
I did the weather mod and got into some problems. At least I think it was, the problem could have been with sh3 commander. It's that crash dive where your frame rate drops very low and your submarine dives really quick. It's not a crash to desktop. Just a game crash.
here is the link to where this is discussed:

http://www.subsim.com/radioroom/showthread.php?t=118212

The correction to the problem is in there too.
edit: the correction to the problem is in the 2 subsim links that are about half-way through the original link that is right above.

Heads up
 

Strange thing is, when I set weather intervals directly in the campaign files, they tend to stick for a long time, but when I start with the Commander, it changes often.
Just one start is enough with it. try it!
:know: