"If you don't like the weather, just wait 15 minutes, and it'll change!" 

This is a common saying in Vermont.  The weather is constantly changing, and temperatures can vary 10 degrees between the bottom and top of Mt. Mansfield.  The best way to deal with these varying conditions?  Layering!  Bringing different layers of clothing will help you be prepared for whatever Mother Nature sends your way. 
This holds true in the summer, also.  The unofficial Vermont summer dress code is shorts and fleece , because it can get chilly on a hike to the top of the mountain, and the temperature can cool down as much as 20 degrees after the sun sets.