Most of the two-million-plus annual visitors to Acadia National Park arrive between April and October, when the park facilities are open and the weather is comfortable. The temperatures during this time fluctuate—it starts to warm up in April, peaks in the 70s by July or August, and cools again in early September. Acadia is crowded during the summer, and prices rise, but the warm days and cool nights make it an ideal time to visit. Blackflies can be abundant—and very annoying—in mid-May and June, but it depends on the year. If you want to see fall foliage, aim for October, when Acadia blossoms into a full range of fall colors.
The Acadia Night Sky festival in September celebrates protecting the park’s stunning night skies, including vivid views of the Milky Way, from light pollution. The festival features art, music, science, and stargazing.
Visit Acadia in April or May, when temperatures are just starting to warm up after winter, the snow is melting, and the crowds haven’t arrived. Yes, shoulder season in Acadia can be rainy and foggy, but it can also offer a magical experience (and less expensive lodging) for travelers who don’t mind getting a little wet.
Winter in Maine isn’t for the faint of heart. Temperatures drop below zero, and about 60 inches of snow fall annually. If you plan to venture outside, make sure you bring the proper clothing and equipment. Also, prepare for many businesses to be closed—as well as the park’s visitor center, museums, picnic areas, Seawall Campground, and many roads.