December in Bar Harbor is the windiest month of the year. In December, the weather in Bar Harbor is typically cold. Average daily high temperature in December is about 1 degree above zero. On average, Bar Harbor has 12 rainy, 7 sunny, 7 partly cloudy, 3 snowy, and 2 cloudy days in December. The rains are usually heavy. December as well as March, April, and May is considered the most uncomfortable time to visit Bar Harbor.