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Monthly climate in St. Mary's, Alaska, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification St. Mary's features a subarctic climate (Dfc). Temperatures typically range between -14 °C (7 °F) and 14 °C (57 °F) through the year, but rarely can drop to -38 °C (-36 °F) or can rise to as high as 30 °C (87 °F). The average annual precipitation amounts to about 747 mm (29.4 inches) and receives 141 rainy days on the 1 mm (0.04 inches) threshold annually. St. Mary's enjoys an average of 1933 hours of sunshine throughout the year, and daylight varies from 5 hours 16 minutes to 19 hours 34 minutes per day.

Monthly average temperatures in St. Mary's, Alaska, United States §

The warmest months in St. Mary's are June, July and August, with daily mean temperatures ranging from 12 to 14 °C (54 - 57 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -14 to -11 °C (7 - 13 °F) throughout the day. On average each year, St. Mary's experiences 0 days above 25 °C (77.0 °F) and 178 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in St. Mary's, Alaska, 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 4°C
(40°F)		 5°C
(41°F)		 5°C
(42°F)		 12°C
(55°F)		 24°C
(75°F)		 24°C
(76°F)		 30°C
(87°F)		 25°C
(78°F)		 18°C
(65°F)		 18°C
(64°F)		 5°C
(41°F)		 5°C
(42°F)
Mean maximum 2°C
(36°F)		 3°C
(37°F)		 2°C
(35°F)		 9°C
(48°F)		 20°C
(68°F)		 22°C
(72°F)		 24°C
(75°F)		 22°C
(73°F)		 17°C
(62°F)		 12°C
(53°F)		 3°C
(38°F)		 4°C
(39°F)
Average high -11°C
(12°F)		 -8°C
(17°F)		 -5°C
(24°F)		 2°C
(36°F)		 12°C
(53°F)		 16°C
(62°F)		 17°C
(62°F)		 15°C
(59°F)		 11°C
(52°F)		 5°C
(41°F)		 -4°C
(25°F)		 -8°C
(18°F)
Daily mean -14°C
(7°F)		 -11°C
(12°F)		 -8°C
(17°F)		 -1°C
(30°F)		 7°C
(45°F)		 13°C
(55°F)		 14°C
(57°F)		 12°C
(54°F)		 8°C
(47°F)		 2°C
(36°F)		 -7°C
(20°F)		 -11°C
(13°F)
Average low -17°C
(2°F)		 -14°C
(7°F)		 -12°C
(11°F)		 -4°C
(24°F)		 3°C
(37°F)		 9°C
(48°F)		 11°C
(51°F)		 9°C
(49°F)		 6°C
(42°F)		 0°C
(32°F)		 -9°C
(16°F)		 -14°C
(8°F)
Mean minimum -31°C
(-24°F)		 -26°C
(-14°F)		 -23°C
(-9°F)		 -18°C
(-1°F)		 -3°C
(26°F)		 4°C
(40°F)		 7°C
(45°F)		 5°C
(41°F)		 0°C
(33°F)		 -8°C
(17°F)		 -19°C
(-3°F)		 -26°C
(-15°F)
Minimum -38°C
(-36°F)		 -32°C
(-25°F)		 -28°C
(-18°F)		 -26°C
(-15°F)		 -5°C
(23°F)		 0°C
(33°F)		 6°C
(43°F)		 3°C
(38°F)		 -3°C
(28°F)		 -12°C
(11°F)		 -28°C
(-17°F)		 -30°C
(-21°F)

Compare climate in St. Mary's with other places

Compare temperature, precipitation, sunshine, UV index in St. Mary's, Alaska, United States with other places around the world.

Monthly average precipitation in St. Mary's, Alaska, United States §

St. Mary's usually has the most precipitation in August, September and October, with an average of 14 rainy days and 85 mm (3.4 inches) of precipitation per month. The driest months in St. Mary's are January, March and April. On average, 44 mm (1.7 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in St. Mary's, Alaska, 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) 30 (1.2) 65 (2.6) 54 (2.1) 47 (1.8) 63 (2.5) 55 (2.2) 63 (2.5) 86 (3.4) 91 (3.6) 78 (3.1) 55 (2.2) 59 (2.3)
Average precipitation days (≥ 1 mm) 7 13 10 8 16 12 12 14 14 14 10 11

Monthly sunshine hours in St. Mary's, Alaska, United States §

The sunniest months in St. Mary's are April, May and June, when the sun shines an average of 9 hours 11 minutes a day. Least sunny months in St. Mary's: January, November and December receive an average of 1 hours 53 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in St. Mary's, Alaska, 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 49 100 175 238 296 300 201 169 156 119 81 43
Mean daily daylight hours 6h 15m 8h 55m 11h 53m 14h 55m 17h 48m 19h 34m 18h 32m 15h 47m 12h 48m 9h 49m 6h 58m 5h 16m

Solar UV radiation in St. Mary's, Alaska, United States §

St. Mary's experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 5 - 6, which corresponds to the Moderate / High category of sun exposure. January, February and November are in the Low exposure category. In these months, the maximum values of the UV index do not exceed 1. For more detailed information, check out our hourly St. Mary's UV Index data.

Average daily maximum UV levels by month for St. Mary's, Alaska, 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) 1 1 3 4 5 6 6 5 3 2 1 1

Detailed Monthly Weather Insights for St. Mary's, Alaska, United States

Discover in-depth weather details for every month in St. Mary's. 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 St. Mary's'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.