The overmitts I use have waterproof palms but just a regular nylon exterior to shed snow

I sewed myself a pair of shell mittens using some polyurethane-coated nylon I "repurposed" from a tent footprint I bought for $0.89 at REI-Outlet. I am not much of a hand with sewing, but I can do really simple stuff. Mittens are simple. I just made my pattern by drawing around my hands on newspaper.

They aren't quite waterproof because I haven't ever bothered to seal the seams, but they do what I want them to do. They weigh just 18 grams for the pair!