Weather does not have much effect on the battery portion, although i wouldn't hold it out in a driving rain storm. Water vs electricity you know. I also wouldn't leave it outside to freeze in upper midwest winters or bake it on the dash during the summer. Just treat it like you would a cell phone and you'll be fine. The MVP seems pretty rugged.
Changing temperatures can effect the
tank because the tank and then liquid expand and contract which changes the pressure inside the tank...leaking. This won't damage anything, just effect performance. Since the protank is glass, it should hold up thru most weather.
I've been thru 2 midwest summers (100 degrees) and winters (below zero) with various equipment without any real problems...not counting the one that I dropped off the roof while hanging xmas lights.