The weather is game breaking and more annoying than it has strategic or tactical value. One game, I was preparing as DM the army 30 minutes before the start of a battle. 15 minutes later both sides were equal in strength and THEN 10 minutes before the first fight the weather changes and the other side doubles its strength. A waste resources + time, because there was no way to win, so I retreated all units. Even during the battle the weather can change which is even more frustrating if you have already put hours into a war trying to get the upperhand when suddenly the weather spoils everything.