Check out what Jungman has to say in the threads below about the weather. He has done a bit of digging into the game files and knows what he is talking about. The problem with the weather is in how the devs implemented it. The change weather timer in the game dosn't have a save game component so it resets each time you reload a save game.
http://www.subsim.com/phpBB/viewtopi...hlight=weather
http://www.subsim.com/phpBB/viewtopi...hlight=weather