Tbh I always loved when it was fog, it adds to gameplay. On the flipside, night only messed with my eyes and made me quit the game when I wanted to play.
I also have nothing against rain.
I think if there wasn't a possiblity to remove night/weather effects externally pitch black night would have been a good idea if it was rare. Otherwise removing it or at least making it 10/20% of the time is the better option.
The other thing is, I really like other times of day in warband and cRPG, I love messing around with them in the scene editor and I rarely see some of those light conditions in game, like sunset, sunrise or any other kind of daylight which changes atmosphere and has nice light angles.