It's not an option in dynasty. It's not a matter of it "working" or "not working", it's set up so that it doesn't happen in dynasty mode. I'm guessing the logic there is if you're playing a dynasty mode game in say, Buffalo, and in-game, you're playing a November or December game, it should be cold and possibly snowy...but if the real date you're playing that game on is in August, you're going to have sunny weather and a temperature around 80 degrees, which would be terribly unrealistic.
It does work in Play Now games, however.