 Average annual precipitation in Bar Harbor is 56.7" (1440 mm).November is the wettest month with 6.5" (165 mm) of precipitation on average, while August is the driest month with 3.3" (84 mm).Precipitation days are spread evenly throughout the year with January averaging the most days, about 11, while August averages the least, about 8, and all other months average 9 or 10 days.