Ah yes, the rain storm of last night... Notice the Rangers hitting mode, during the steady downfall?
This jewel of wisdom, is seldom remembered, certainly not taught, in today's plate instruction(s):
The hitters body "naturally" finds correct stability in his legs & core - cutting down his swing.
The body "naturally" corrects itself, to keep from falling down! It's a natural, focused element in each.
Of course, pitch selection stays the same, but when one's head is not moving... you see the pitch.
The secondary element, of this process is... the weight of the bat increases from being wet.
Sure, bat speed IS important, but control is key. A slightly heavier bat gives that element to the batter.
Being a MLB hitter is "natural" for most of the players. They're not using the "naturalness already there.
A Rain Storm *CAN turn on the hitters "AUTO MODE". Just keep your eyes open and clear.

HubZ not sure if you are a golfer but this is almost exactly the same approach to hitting a knock down shot and the exact same approach to playing in the wind. Stability and shortened swings concentrating on solid crisp contact seem to work well in both sport.