ORIGINAL: Greg / MO
Exactly. I've used feathers for over a decade, and never worried about the weather. If you say you're rusty, I'd bet the differences in POI (point of impact) can be accounted for in shooting error alone. I know that I always carry one arrow in my quiver tipped with a field point, and I've taken it out -- completely soaked during a downpour -- before getting down from my treestand, picked out a leaf and centered it almost every time I've tried it.
I did that once,the leaf turned out to be a rock and the last I saw of my arrow had sparks fluing off of it flying about 100 yards through the woods in pieces.