Rain can affect microwave frequency. It is called rain fade. Some cell towers use microwave for backhaul linking. If their microwave link is already marginal and doesn't have enough signal strength, then it will degrade during raining (or even fogging), especially via a long distance. Heavy snow can have an even bigger effect. It is because certain frequencies are more affected by water than others, and that is in the microwave range.
If you have satellite TV, it will suffer from this effect as well, again, if it doesn't have enough margin in the first place.
Looking at some of the posts here, oh, yea, has NOTHING to do with it. Typical HoFo Know It Alls.
I have a microwave range installed right in my kitchen that can melt snow just fine Mr. Know It All!