I've been on DirecTV since 2003. Weather can definitely cause signal loss. The original dish position that I had was being obstructed by a tree, so heavy cloud cover, rainstorms, snowstorms, and even high winds would cause signal loss. I had another installer come out, and he moved the dish to a better location, so it wasn't as sensitive to the weather.
I still get signal loss if a snowstorm comes through as the temperature drops from above to below freezing. Then the snowflakes cover the receiving head at the focus of the dish. This is very inconvenient, as I have to get out the ladder and slog through the snow, and climb on the roof so I can brush off the receiving head with a broom.
I'm thinking about going with internet TV. YouTube, ME TV, Netflix, etc have plenty of entertainment. And I wouldn't miss the news channels; they're just so depressing anyway.