I flew my fixed wing drone on a winter day with light (almost imperceptible) drizzle. Looking at your car windshild there were a few tiny specs of precip showing up. Temps on the ground were slightly above freezing. I figured I was fine to fly. After an hour flight I took over manual control to land in a really tight constrained area and nose just dropped. I had to hold a ton of up elevator and a lot of power to fly the approach. Everything ended fine, but when I walked over to pick up the airplane, the front 1/3 of everything was sheeted in ice. Completely messed up the CG. I feel a little lucky things didn't end worse, and hopefully I learned something that day about weather. I did get 2,500 24 megapixel images and made a great map, so it all worked out.