I love hunting in the rain. Unless it's a downpour, I'm out there. Steady all day drizzles can be dynamite. I like the very beginning of thunderstorms, too, when the wind is picking up and sky gets dark. Right before the lightning, thunder, and heavy rain close in, the deer are up and moving. The tail end immediately following a storm is good, too. Fair weather hunters get what they hunt for, butterflies & sunshine.
True story & cautionary tale. I shot my first mature buck of this season in late August. He was a 10pt in velvet, coming out to the beans for one quick bite before the looming storm hit. Otherwise he was almost exclusively nocturnal. I could hear thunder approaching and the wind was swaying my tree. It was time to climb down & take cover, then he walked 15yds under my stand & stood broadside still at field edge. Of course I took the shot. It was a perfect hit in the pumper and he was down immediately, no trailing needed. I climbed down and when I grabbed the fence to step over it, lightning hit somewhere on the line. It burnt my hand & leg, blew the bow from my other hand, and arced about 6ft to my brother who wasn't even near the fence. I immediately knew what happened but my entire body was numb & tingled and I couldn't move. It was like buck fever but 100x worse, and painful. Luckily it just stunned me and I was able to get my buck home without myself dying. His velvet unfortunately got ruined in the rain and his crash. That evening my wife asked what was wrong with my face. I looked in the mirror and had a severe case of welders burn.
Point of the story is deer move very well in rain and on the edge of thunderstorms, but be very careful or you might be the one getting smoked.