The rain shouldn't affect your arrow flight adversely. It is early in the season so if you don't feel like getting wet don't bother, but in a couple weeks if you can hunt you should no matter what the weather. Just make a good shot. You can't go hunting thinking about what will happen if you make a bad shot. Think positive and be confident in your abilities. If you aren't confident that you can make a 30 ayrd shot in the rain then you shouldn't shoot it in the sun either.