Acadia National Park Weather by Month (2026 Guide)

Acadia National Park’s weather is shaped by the Atlantic: summers are mild with highs near 79°F and frequent morning fog, while winters bring nor’easters, sea wind, and enough snow to close most park roads. Timing matters here — the Park Loop Road is only open April 15 through December 1, and Cadillac Mountain vehicle reservations run May 20 to October 25.

This guide covers average temperatures, precipitation, fog, and what to expect at Acadia National Park every month of the year, per NPS.gov and long-term climate records.

Monthly Weather Overview

The table below shows long-term climate averages for Bar Harbor (sea level), the park’s gateway town on Mount Desert Island, based on NOAA 1981–2010 U.S. Climate Normals. Conditions on Cadillac Mountain (1,530 ft — the highest point on the U.S. Atlantic coast) can be drastically different from Bar Harbor at the same hour, per NPS.gov: colder, windier, and often inside cloud while the village is clear.

Winter: December–February

December through February is Acadia’s quietest period. Bar Harbor averages highs of 31–37°F with overnight lows in the teens, and the NPS describes winter conditions as variable, ranging from 14–35°F. Snow arrives in waves — coastal storms can drop heavy, wet snowfall, then a thaw and ocean air can strip it back within days. December through March each average roughly 8–12 inches of snowfall in town.

The Park Loop Road and the park’s other paved roads are closed to vehicles from December 1 through April 14, per NPS.gov. The park itself remains open year-round. The carriage roads stay open with seasonal closures and become Acadia’s cross-country skiing and snowshoeing network, while the Schoodic Loop Road on the quieter mainland peninsula remains drivable year-round.

Most lodges, campgrounds, and visitor facilities are closed in winter, and nearby Bar Harbor runs at a fraction of its summer pace. For prepared visitors, the reward is a rocky, spruce-dark coastline in sea smoke and snow that very few of Acadia’s four million annual visitors ever see.

Spring: March–May

Spring in Acadia is a slow, foggy thaw. The NPS characterizes the season as foggy with temperatures anywhere from 30–70°F — March can still deliver snowstorms, while a sunny May afternoon feels like early summer. Sea fog becomes a regular feature as warming air moves over the still-cold Gulf of Maine, and it can erase coastal views for hours at a time.

The season’s key date is April 15, when the Park Loop Road and other paved park roads reopen to vehicles, per NPS.gov. Unpaved roads follow on May 15. Facilities come back online through May: Blackwoods Campground opens May 1, the Hulls Cove Visitor Center on May 1, Seawall and Schoodic Woods campgrounds on May 20, and the Jordan Pond House restaurant on May 16.

By late May, Acadia is effectively in early-summer condition with a fraction of the crowds: trails are clear, campgrounds like Blackwoods are open, and lodging rates in Bar Harbor haven’t hit their July peak. Families planning a spring or early-summer trip can build on our 3-day Acadia family itinerary.

Summer: June–August

Summer is peak season for both weather and crowds. July and August bring average highs of 78–79°F in Bar Harbor, with the NPS noting daytime ranges anywhere from 45–90°F across the park. Ocean temperatures top out at 50–60°F — a genuine cold plunge even in August — while inland lakes are friendlier at 55–70°F, per NPS.gov.

June is warm (average high 74°F) but is Acadia’s foggiest summer month. Morning fog banks regularly swallow the Park Loop Road coastline and burn off by midday — or don’t. Build flexibility into sunrise plans, especially Cadillac Mountain sunrise reservations, which are non-refundable when fog wins.

July is the warmest and most reliable month: long days, highs near 79°F, every facility open, and the full trail and carriage road network available. It is also the start of Acadia’s most crowded stretch — parking at Jordan Pond and Sand Beach fills by mid-morning, and the Island Explorer shuttle becomes the sane way to move around the east side.

August is nearly identical to July (highs ~78°F) and slightly drier, with the season’s warmest ocean and lake temperatures. Crowds peak in the first half of the month. By late August, evenings cool noticeably — a preview of Acadia’s outstanding fall.

Fall: September–November

September is widely considered Acadia’s best month. Crowds thin after Labor Day, average highs sit near 71°F, the fog machine of early summer eases, and the ocean is as warm as it gets. All facilities remain open, and hiking conditions across the park’s exposed granite ridgelines are at their year-round best.

October is Acadia’s signature show. Fall foliage typically peaks in mid-October, per NPS.gov, and the combination of red maples against dark spruce and pink granite draws a second visitation surge — October weekends can rival summer. It’s also the start of the wet season: October and November are the year’s rainiest months (4.2 and 4.4 inches). Our 4-day Acadia fall foliage itinerary is built around this window.

November winds the park down. Campgrounds close in October (Blackwoods runs through October 19, Seawall and Schoodic Woods through October 12), Cadillac vehicle reservations end October 25, the Hulls Cove Visitor Center closes October 31, and the Park Loop Road closes to vehicles December 1. Expect raw, wet, windy weather with highs in the 40s — and near-total solitude.

Best Time to Visit Acadia National Park

The right month depends on your priorities. Each season offers a distinct experience — and each has trade-offs:

For most first-time visitors, early September through mid-October delivers the best blend of weather, open facilities, and manageable crowds — with mid-October adding peak foliage at the cost of busy weekends.

What to Pack by Season

Acadia’s coastal weather shifts fast, and the park’s peaks behave differently from the villages below them. Layers and rain protection belong in your pack in every month of the year.

For a full checklist, see the national park packing list by season.