So, don't beat yourself up too much, because the weather isn't quite the show-stopper previous posters made it out to be--particularly insomuch as east-coast is generally not great for one reason or other (too hot or too rainy). My mother lives in Maine, and I've been up to see her enough to know that Maine's winters are horrible, but I'll take their summers.
Yes, most folks in the US do most of their traveling in the summer, but still Disney has their busiest time in winter.
I think the issue at hand for Maine is that the winters are often bad enough to stop travel cold. Even if travel isn't stopped, outdoor attractions would not be reasonably attended for half the year or more.