Tool
Best Time to Visit Acadia National Park
Four things decide when to come, and none of them line up. This puts the measured sea temperature, the computed daylight, the fly season and the foliage window on one axis so you can see where the gap is.
The four windows that matter
Nobody writes down why September is the usual answer, because the reason is a gap rather than a fact: the flies have gone, the sea is still at its warmest, and the colour has not started. Hatched is the band you are trying to miss.
Why June disappoints swimmers
Daylight peaks at the solstice; the sea does not peak until late August, because water takes most of the summer to catch up with the air above it. Two months of lag between the two lines is the single most useful thing on this page, and the reason a long June day is not a warm one in the water.
- Sea temperature, left axis
- Daylight, right axis
- January: 9.2 hours of daylight, sea 34.3 degrees Fahrenheit.
- February: 10.5 hours of daylight, sea 31.2 degrees Fahrenheit.
- March: 11.9 hours of daylight, sea 34.9 degrees Fahrenheit.
- April: 13.5 hours of daylight, sea 40.1 degrees Fahrenheit.
- May: 14.8 hours of daylight, sea 46.6 degrees Fahrenheit.
- June: 15.5 hours of daylight, sea 52.1 degrees Fahrenheit.
- July: 15.2 hours of daylight, sea 56.3 degrees Fahrenheit.
- August: 14.0 hours of daylight, sea 58.2 degrees Fahrenheit.
- September: 12.5 hours of daylight, sea 58.1 degrees Fahrenheit.
- October: 11.0 hours of daylight, sea 54.7 degrees Fahrenheit.
- November: 9.6 hours of daylight, sea 49.0 degrees Fahrenheit.
- December: 8.9 hours of daylight, sea 40.4 degrees Fahrenheit.
Month by month
| Month | Daylight | Sea | Verdict | What it is like |
|---|---|---|---|---|
| January7:05 AM to 4:19 PM | 9.2 h | 34°F | Empty and hard | Nine hours of light, sea near freezing, most of the Park Loop Road shut. The carriage roads become ski and snowshoe trails and you will have them almost to yourself, which is either the whole point or a reason to come another time. |
| February6:32 AM to 5:01 PM | 10.5 h | 31°F | The coldest water of the year | The sea bottoms out now rather than in January, because water lags air. Light is returning but the island is still in winter mode, with few places open in Bar Harbor. |
| March6:45 AM to 6:39 PM | 11.9 h | 35°F | Mud, and not much else | The awkward month. Trails thaw and refreeze, the snow is going, and summer has not started. Days are back to twelve hours, which is the one thing in its favour. |
| April5:48 AM to 7:17 PM | 13.5 h | 40°F | Waking up, still quiet | Thirteen and a half hours of light and almost nobody about. Facilities are opening in stages and the higher trails can still be icy in the shade. Good for the coast paths, early for the summits. |
| May5:05 AM to 7:53 PM | 14.8 h | 47°F | Green, cheap, and buggy from mid-month | The best value fortnight of the year is the first half of May. Then the black flies arrive and, until early summer, they are a genuine factor on any inland or wooded trail. The open coast is the mildest place to be. |
| June4:47 AM to 8:19 PM | 15.5 h | 52°F | Long days, flies, building crowds | The longest days of the year, over fifteen hours of light, and the sea finally past fifty. Black flies are still out for most of the month. Crowds build steadily toward the Fourth of July. |
| July5:02 AM to 8:14 PM | 15.2 h | 56°F | Peak everything | Warmest, busiest, and the month that most needs an early alarm and the Island Explorer. Car parks at Sand Beach and Jordan Pond fill by mid-morning. Boats and swimming are at their most reliable. |
| August5:35 AM to 7:37 PM | 14.0 h | 58°F | Warmest water, biggest crowds | The sea reaches its annual peak, which on this coast still means the fifties. Everything is open and everything is full. If you are coming in August, book lodging early and treat parking as a solved problem only if you use the shuttle. |
| September6:11 AM to 6:43 PM | 12.5 h | 58°F | The best compromise in the year | Water as warm as August, crowds thinning after Labor Day, twelve and a half hours of light, and facilities still open. If someone asks for one month, this is usually the answer. |
| October6:47 AM to 5:48 PM | 11.0 h | 55°F | Foliage, and the reason to book ahead | Peak colour arrives on the coast well after the mountains, in the second and third weeks. Lodging in Bar Harbor is at its tightest of the year outside high summer, and the light is the best it gets. |
| November6:28 AM to 4:05 PM | 9.6 h | 49°F | Closing down, opening up | Facilities wind down and the island empties. In exchange, from the middle of the month Cadillac starts taking the first sunrise in the country, and the summit is a very different place with nobody on it. |
| December7:02 AM to 3:53 PM | 8.9 h | 40°F | Dark, and first light | The shortest days of the year, under nine hours. Cadillac holds the first-sunrise stint throughout, and a clear December dawn from the summit is the single most distinctive thing the park offers in winter, weather and road access permitting. |
Sunrise and sunset are computed for Bar Harbor on the fifteenth of each month. Sea temperature is the mean of the daily means recorded by NOAA station 8413320 over the past twelve months, so a warm or cold year moves it.
If you are coming for one thing
- Foliage: the second and third weeks of October. Later than the Maine mountains, which catches people out. Track the season.
- Swimming: late August, and manage expectations. Echo Lake beats the ocean. Today’s sea temperature.
- Hiking without flies: July onward, or the first half of May before they emerge. Check the fly season.
- First sunrise in the country: the ten weeks or so this page computes for Cadillac, from the second half of November into late January. See today’s winner.
- Quiet: the first half of May, or November. Both trade facilities for having the place to yourself.
- Bar Island and the tidepools: any month, but only around low water. Tide windows.
Common questions
What is the best month to visit Acadia National Park?
September, for most people and most purposes. The sea is as warm as it gets all year, the crowds thin after Labor Day, there are still twelve and a half hours of daylight, and facilities are open. October is the stronger choice if foliage is the reason you are coming, at the cost of the tightest lodging of the year.
When is peak foliage in Acadia?
The second and third weeks of October on the coast, which is noticeably later than the Maine mountains. Colour moves from the north and the high ground down to the shore, so a trip planned around the state's inland peak will arrive at Acadia too early.
Is the water warm enough to swim at Acadia?
Not by most people's standards. The NOAA sensor in Bar Harbor peaks around the high fifties Fahrenheit in late August, and Sand Beach sits on open ocean, so a swim there is brief and loud. Echo Lake, on the western side of the island, is fresh water and genuinely warmer.
When are black flies bad in Acadia?
From roughly the middle of May to the end of June. They are worst inland, near running water and on still, humid days; the open coast and a sea breeze are the mildest places on the island during those weeks.
When does Cadillac Mountain get the first sunrise in America?
For around ten weeks in midwinter, not for half the year as the claim is usually repeated. On our own calculation, ranking Cadillac against Mars Hill, West Quoddy Head, Katahdin and Eastport, Cadillac leads from the second half of November into late January. For most of the year the first light lands on Mars Hill or West Quoddy Head.
Is Acadia worth visiting in winter?
For the carriage roads on skis or snowshoes, and for a summit sunrise, yes. For everything else, it is a different park: most of the Park Loop Road closes, daylight drops under nine hours, and much of Bar Harbor shuts. Check road and facility status with the park before travelling.
