Dual-type weather could also cause problems with certain quests and activities require a particular weather type, so no.
It would be a lot of work for very little gain, which can also be obtained by learning weather patterns for a region.

There's a better way. Add MMM runes that affect the weather. That way, you can make a custom dungeon with your preferred enemy type and weather. You could do it solo or with friends or even a pickup group looking for the same enemies.

SCH weather spells don't affect magian trials because the effect needs to be on the monster, not the player. Besides, it wouldn't make sense to let one job cheat a trial goal.