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Monthly climate in Grand Isle, Maine, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification Grand Isle features a humid continental climate (Dfb). Temperatures typically range between -11 °C (13 °F) and 19 °C (66 °F) through the year, but rarely can drop to -32 °C (-24 °F) or can rise to as high as 33 °C (92 °F). The average annual precipitation amounts to about 1166 mm (45.9 inches) and receives 141 rainy days on the 1 mm (0.04 inches) threshold annually. Grand Isle enjoys an average of 2764 hours of sunshine throughout the year, and daylight varies from 8 hours 30 minutes to 15 hours 52 minutes per day.

Monthly average temperatures in Grand Isle, Maine, United States §

The warmest months in Grand Isle are June, July and August, with daily mean temperatures ranging from 15 to 19 °C (60 - 66 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -11 to -8 °C (13 - 18 °F) throughout the day. On average each year, Grand Isle experiences 25 days above 25 °C (77.0 °F) and 162 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Grand Isle, Maine, United States. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 9°C
(49°F)		 6°C
(44°F)		 16°C
(60°F)		 19°C
(66°F)		 31°C
(88°F)		 33°C
(92°F)		 32°C
(90°F)		 31°C
(88°F)		 28°C
(82°F)		 21°C
(71°F)		 21°C
(69°F)		 14°C
(57°F)
Mean maximum 4°C
(39°F)		 6°C
(42°F)		 9°C
(48°F)		 16°C
(61°F)		 27°C
(81°F)		 27°C
(81°F)		 29°C
(85°F)		 28°C
(84°F)		 26°C
(79°F)		 19°C
(67°F)		 15°C
(60°F)		 9°C
(48°F)
Average high -6°C
(21°F)		 -5°C
(23°F)		 -0°C
(32°F)		 7°C
(45°F)		 16°C
(61°F)		 20°C
(69°F)		 24°C
(75°F)		 23°C
(74°F)		 18°C
(65°F)		 11°C
(52°F)		 3°C
(37°F)		 -4°C
(25°F)
Daily mean -11°C
(13°F)		 -9°C
(15°F)		 -5°C
(24°F)		 3°C
(37°F)		 10°C
(51°F)		 15°C
(60°F)		 19°C
(66°F)		 18°C
(65°F)		 13°C
(56°F)		 7°C
(45°F)		 -1°C
(31°F)		 -8°C
(18°F)
Average low -15°C
(6°F)		 -14°C
(7°F)		 -9°C
(16°F)		 -2°C
(29°F)		 5°C
(41°F)		 10°C
(50°F)		 14°C
(57°F)		 13°C
(56°F)		 8°C
(47°F)		 3°C
(38°F)		 -5°C
(24°F)		 -12°C
(10°F)
Mean minimum -26°C
(-14°F)		 -25°C
(-13°F)		 -21°C
(-5°F)		 -9°C
(16°F)		 -2°C
(29°F)		 3°C
(38°F)		 8°C
(46°F)		 6°C
(44°F)		 1°C
(34°F)		 -4°C
(25°F)		 -16°C
(3°F)		 -23°C
(-9°F)
Minimum -32°C
(-24°F)		 -27°C
(-16°F)		 -24°C
(-12°F)		 -13°C
(8°F)		 -4°C
(26°F)		 0°C
(33°F)		 5°C
(42°F)		 5°C
(42°F)		 -2°C
(28°F)		 -9°C
(17°F)		 -19°C
(-1°F)		 -26°C
(-14°F)

Compare climate in Grand Isle with other places

Compare temperature, precipitation, sunshine, UV index in Grand Isle, Maine, United States with other places around the world.

Monthly average precipitation in Grand Isle, Maine, United States §

Grand Isle usually has the most precipitation in April, October and November, with an average of 12 rainy days and 119 mm (4.7 inches) of precipitation per month. The driest months in Grand Isle are February, March and August. On average, 78 mm (3.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Grand Isle, Maine, United States. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 89 (3.5) 74 (2.9) 77 (3.0) 119 (4.7) 97 (3.8) 92 (3.6) 93 (3.7) 84 (3.3) 100 (3.9) 121 (4.7) 119 (4.7) 102 (4.0)
Average precipitation days (≥ 1 mm) 9 11 10 14 14 13 13 11 11 12 12 11

Monthly sunshine hours in Grand Isle, Maine, United States §

The sunniest months in Grand Isle are June, July and August, when the sun shines an average of 10 hours 46 minutes a day. Least sunny months in Grand Isle: January, November and December receive an average of 4 hours 31 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Grand Isle, Maine, United States. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 116 180 231 223 284 320 341 329 255 182 151 147
Mean daily daylight hours 8h 56m 10h 16m 11h 56m 13h 39m 15h 7m 15h 52m 15h 27m 14h 8m 12h 30m 10h 48m 9h 17m 8h 30m

Solar UV radiation in Grand Isle, Maine, United States §

Grand Isle experiences the highest level of ultraviolet (UV) radiation in May, June and August, when the maximum UV index can reach values of 8 - 10, which corresponds to the Very High category of sun exposure. January, February and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Grand Isle UV Index data.

Average daily maximum UV levels by month for Grand Isle, Maine, United States. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 2 3 5 7 8 10 8 8 7 4 3 2

Detailed Monthly Weather Insights for Grand Isle, Maine, United States

Discover in-depth weather details for every month in Grand Isle. Click through the links below for comprehensive overviews of temperature trends, precipitation levels, sunshine hours, and solar UV radiation specifics. Whether planning a visit or simply curious about Grand Isle's climate nuances, these monthly breakdowns provide the information you need for an informed understanding of what to expect throughout the year.

Each link leads to a detailed account of the typical weather conditions for that month, providing both locals and tourists with vital information to plan their daily activities, wardrobe, and travel itineraries accordingly.