nomadseason

Monthly climate in Southwest Harbor, Maine, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Southwest Harbor features a humid continental climate (Dfb).Temperatures typically range between -1 °C (30 °F) and 16 °C (62 °F) through the year, but rarely can drop to -16 °C (3 °F) or can rise to as high as 21 °C (70 °F).The average annual precipitation amounts to about 1332 mm (52.4 inches) and receives 129 rainy days on the 1 mm (0.04 inches) threshold annually.Southwest Harbor enjoys an average of 2943 hours of sunshine throughout the year, and daylight varies from 8 hours 54 minutes to 15 hours 26 minutes per day.

Monthly average temperatures in Southwest Harbor, Maine, United States §

The warmest months in Southwest Harbor are July, August and September, with daily mean temperatures ranging from 15 to 16 °C (59 - 62 °F) throughout the day. The coldest temperatures usually occur in January, February and March, when daily mean temperatures range from -1 to 1 °C (30 - 34 °F) throughout the day. On average each year, Southwest Harbor experiences 0 days above 25 °C (77.0 °F) and 81 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Southwest Harbor, 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 11°C
(52°F)		 10°C
(50°F)		 9°C
(49°F)		 13°C
(55°F)		 16°C
(61°F)		 18°C
(64°F)		 20°C
(69°F)		 21°C
(70°F)		 20°C
(69°F)		 18°C
(64°F)		 16°C
(62°F)		 14°C
(57°F)
Mean maximum 9°C
(49°F)		 8°C
(47°F)		 8°C
(47°F)		 10°C
(50°F)		 14°C
(58°F)		 16°C
(62°F)		 19°C
(67°F)		 20°C
(68°F)		 18°C
(65°F)		 17°C
(63°F)		 15°C
(59°F)		 12°C
(55°F)
Average high 2°C
(36°F)		 2°C
(36°F)		 3°C
(38°F)		 6°C
(44°F)		 10°C
(50°F)		 14°C
(57°F)		 16°C
(61°F)		 17°C
(63°F)		 16°C
(61°F)		 13°C
(56°F)		 9°C
(48°F)		 4°C
(40°F)
Daily mean -1°C
(30°F)		 -1°C
(31°F)		 1°C
(34°F)		 5°C
(41°F)		 8°C
(48°F)		 12°C
(54°F)		 15°C
(59°F)		 16°C
(62°F)		 15°C
(59°F)		 12°C
(54°F)		 6°C
(44°F)		 1°C
(35°F)
Average low -4°C
(25°F)		 -4°C
(26°F)		 -1°C
(30°F)		 3°C
(38°F)		 7°C
(46°F)		 11°C
(53°F)		 14°C
(57°F)		 16°C
(60°F)		 14°C
(58°F)		 11°C
(51°F)		 4°C
(40°F)		 -1°C
(30°F)
Mean minimum -14°C
(7°F)		 -13°C
(9°F)		 -11°C
(12°F)		 -1°C
(30°F)		 4°C
(39°F)		 8°C
(47°F)		 12°C
(54°F)		 14°C
(57°F)		 11°C
(52°F)		 5°C
(42°F)		 -4°C
(25°F)		 -10°C
(14°F)
Minimum -16°C
(3°F)		 -14°C
(6°F)		 -14°C
(7°F)		 -3°C
(27°F)		 3°C
(37°F)		 8°C
(46°F)		 12°C
(53°F)		 13°C
(56°F)		 9°C
(48°F)		 2°C
(36°F)		 -10°C
(14°F)		 -16°C
(4°F)

Compare climate in Southwest Harbor with other places

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

Monthly average precipitation in Southwest Harbor, Maine, United States §

Southwest Harbor usually has the most precipitation in April, November and December, with an average of 13 rainy days and 145 mm (5.7 inches) of precipitation per month.The driest months in Southwest Harbor are March, July and August. On average, 84 mm (3.3 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Southwest Harbor, 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) 113 (4.4) 107 (4.2) 83 (3.3) 143 (5.6) 105 (4.1) 95 (3.7) 82 (3.2) 87 (3.4) 105 (4.2) 119 (4.7) 139 (5.5) 154 (6.1)
Average precipitation days (≥ 1 mm) 10 12 10 13 11 9 10 8 9 11 13 13

Monthly sunshine hours in Southwest Harbor, Maine, United States §

The sunniest months in Southwest Harbor are June, July and August, when the sun shines an average of 10 hours 26 minutes a day.Least sunny months in Southwest Harbor: January, November and December receive an average of 5 hours 22 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Southwest Harbor, 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 141 188 257 244 292 316 318 325 281 224 183 170
Mean daily daylight hours 9h 16m 10h 28m 11h 57m 13h 29m 14h 47m 15h 26m 15h 5m 13h 55m 12h 27m 10h 55m 9h 35m 8h 54m

Solar UV radiation in Southwest Harbor, Maine, United States §

Southwest Harbor 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, November 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 Southwest Harbor UV Index data.

Average daily maximum UV levels by month for Southwest Harbor, 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 4 5 7 9 10 8 8 7 5 3 2