I've said this before. I live in "snow country" in Upstate New York,which probably gets as much snow as they get in Maine, and in the almost 13 years with DirecTV I've never had a single snow related outage. It can't be just me. Nobody uses dish covers or heaters around here either. Usually the only time in winter somebody loses the signal is if their dish gets blown out of alignment in a heavy wind.
I'm not a techie, but as I understand it, it all depends on the angle of your dish in relation to the satellites. The further North you are the straighter the dish and the less of a "bowl" it makes to collect snow. When "nor'easters" come up the coast from the south, folks in states like Maryland and Virginia do have issues, no question about it, but this far north everything is normal.
Still, it doesn't hurt to be cautious. Make sure your dish is locked down tight and in perfect alignment. And regardless where we live, it's always a good idea to have it in an accessible place just in case you do have to get to it for some reason.