Just by chance, I shot a 3d course yesterday in the pouring rain, and I do mean cats & dogs. I was shooting with a WB and feathers to boot. No problems on anything inside 40 yards. If there was any effect on the arrows, it was too small for me to notice.
Shooting in a summertime downpour, is a riot. It also lets you know what you can trust and what you can't trust, come hunting time.
you can buy something called "no-snow: i think, its a waterproofing spray for boots, leather, packs, etc. Its supposedly scent free. It also will lube the whiskers for you and youll be fine.
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Hoyt VTEC 28" @ 74# 283 ft/s
GTProHunters 5575 wraped and Blazed
100 Grn Rcky Mtn Snypers & Stinger 4 Blade
STS, QAD Ultra Rest Pro