I have had some great opportunities and taken some very good deer in the rain, and also during snowfall. Seems like the deer move quite a bit just before and during the beginning of a front. Weird thing is, I've noticed this when fishing also.......I guess it is something about the wild critters knowing that things will be "shut-down" for a period of time...so they try to fit in a bit of "last-minute shopping"....Don't know why this is, I just know I've witnessed it too many times for it to be a coincidence.