Climate and Average Weather Year Round in Acadia National Park United States

In Acadia National Park, the summers are comfortable; the winters are freezing, snowy, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 13°F to 76°F and is rarely below -2°F or above 83°F.

Based on the tourism score, the best time of year to visit Acadia National Park for warm-weather activities is from late June to early September.

The warm season lasts for 3.4 months, from June 4 to September 16, with an average daily high temperature above 67°F. The hottest month of the year in Acadia National Park is July, with an average high of 75°F and low of 58°F.

The cold season lasts for 3.3 months, from December 3 to March 14, with an average daily high temperature below 39°F. The coldest month of the year in Acadia National Park is January, with an average low of 15°F and high of 31°F.

In Acadia National Park, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Acadia National Park begins around June 25 and lasts for 4.2 months, ending around October 31.

The clearest month of the year in Acadia National Park is September, during which on average the sky is clear, mostly clear, or partly cloudy 61% of the time.

The cloudier part of the year begins around October 31 and lasts for 7.9 months, ending around June 25.

The cloudiest month of the year in Acadia National Park is May, during which on average the sky is overcast or mostly cloudy 57% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Acadia National Park varies throughout the year.

The wetter season lasts 9.6 months, from October 16 to August 2, with a greater than 28% chance of a given day being a wet day. The month with the most wet days in Acadia National Park is December, with an average of 9.9 days with at least 0.04 inches of precipitation.

The drier season lasts 2.4 months, from August 2 to October 16. The month with the fewest wet days in Acadia National Park is August, with an average of 7.5 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Acadia National Park changes throughout the year.

Rain alone is the most common for 11 months, from February 5 to January 18. The month with the most days of rain alone in Acadia National Park is June, with an average of 9.3 days.

Snow alone is the most common for 2.6 weeks, from January 18 to February 5. The month with the most days of snow alone in Acadia National Park is January, with an average of 3.0 days.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Acadia National Park experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Acadia National Park. The month with the most rain in Acadia National Park is November, with an average rainfall of 4.2 inches.

The month with the least rain in Acadia National Park is January, with an average rainfall of 1.9 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Acadia National Park experiences extreme seasonal variation in monthly snowfall.

The snowy period of the year lasts for 5.8 months, from October 27 to April 21, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Acadia National Park is January, with an average snowfall of 12.7 inches.

The snowless period of the year lasts for 6.2 months, from April 21 to October 27. The least snow falls around July 20, with an average total accumulation of 0.0 inches.

The length of the day in Acadia National Park varies significantly over the course of the year. In 2024, the shortest day is December 21, with 8 hours, 51 minutes of daylight; the longest day is June 20, with 15 hours, 32 minutes of daylight.

The earliest sunrise is at 4:48 AM on June 15, and the latest sunrise is 2 hours, 24 minutes later at 7:12 AM on November 2. The earliest sunset is at 3:53 PM on December 9, and the latest sunset is 4 hours, 28 minutes later at 8:21 PM on June 25.

Daylight saving time (DST) is observed in Acadia National Park during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Acadia National Park experiences some seasonal variation in the perceived humidity.

The muggier period of the year lasts for 2.7 months, from June 21 to September 13, during which time the comfort level is muggy, oppressive, or miserable at least 3% of the time. The month with the most muggy days in Acadia National Park is August, with 3.2 days that are muggy or worse.

The least muggy day of the year is March 2, when muggy conditions are essentially unheard of.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Acadia National Park experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.4 months, from October 9 to April 23, with average wind speeds of more than 7.9 miles per hour. The windiest month of the year in Acadia National Park is February, with an average hourly wind speed of 10.0 miles per hour.

The calmer time of year lasts for 5.6 months, from April 23 to October 9. The calmest month of the year in Acadia National Park is August, with an average hourly wind speed of 5.9 miles per hour.

The predominant average hourly wind direction in Acadia National Park varies throughout the year.

The wind is most often from the north for 2.4 months, from February 8 to April 20, with a peak percentage of 38% on February 11. The wind is most often from the south for 5.5 months, from April 20 to October 6, with a peak percentage of 45% on July 13. The wind is most often from the west for 4.1 months, from October 6 to February 8, with a peak percentage of 42% on January 1.

Acadia National Park is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.2 months, from July 3 to October 9, with an average temperature above 53°F. The month of the year in Acadia National Park with the warmest water is August, with an average temperature of 57°F.

The time of year with cooler water lasts for 3.4 months, from January 15 to April 26, with an average temperature below 41°F. The month of the year in Acadia National Park with the coolest water is March, with an average temperature of 37°F.

To characterize how pleasant the weather is in Acadia National Park throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Acadia National Park for general outdoor tourist activities is from late June to early September, with a peak score in the last week of July.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Acadia National Park for hot-weather activities is from mid July to mid August, with a peak score in the last week of July.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Acadia National Park typically lasts for 5.5 months (166 days), from around April 30 to around October 13, rarely starting before April 14 or after May 17, and rarely ending before September 26 or after October 31.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Acadia National Park should appear around May 18, only rarely appearing before May 9 or after May 28.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.4 months, from May 9 to August 23, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest month of the year in Acadia National Park is July, with an average of 6.5 kWh.

The darker period of the year lasts for 3.5 months, from October 30 to February 12, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest month of the year in Acadia National Park is December, with an average of 1.4 kWh.

For the purposes of this report, the geographical coordinates of Acadia National Park are 44.351 deg latitude, -68.244 deg longitude, and 0 ft elevation.

The topography within 2 miles of Acadia National Park is essentially flat, with a maximum elevation change of 0 feet and an average elevation above sea level of 0 feet. Within 10 miles is also essentially flat (0 feet). Within 50 miles is also essentially flat (0 feet).

The area within 2 miles of Acadia National Park is covered by trees (76%) and artificial surfaces (14%), within 10 miles by water (60%) and trees (36%), and within 50 miles by water (57%) and trees (38%).