In my experience, neither rain nor high wind will keep deer from moving. The movement isn't always in sync with the "normal" pattern (i.e., in high wind, deer often run from one place to another unpredictably rather than move steadily along in established patterns), but deer will move nonetheless. In fact, I have probably seen more deer on average on rainy days than in any other weather. The second-best buck I ever killed (154 B&C 12-pointer) was on a windy day with occasional showers. I made myself get back in the stand after an hour lunch break, and at 2:15 pm he came in following a big old doe.
It also helps to be equipped to stay out there when it gets messy. That's one reason I have become mostly a ground blind hunter. The more comfortable I am, the longer I can stay put, and the better chances I have of seeing deer. Stillhunting works best for me in windy, but not rainy, weather. Wet gun, hands, and gear seems to be almost an equal disadvantage for me as the advantage from the cover of wet terrain. Plus, as I said, deer seem to move more in rainy weather anyway, so I am better off sitting.
If I wake up to rain or high wind, I am even more motivated to get out there because I know my chances might actually increase.
