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Monthly climate in Helena Valley Northwest, Montana, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Helena Valley Northwest features a humid continental climate (Dfb).Temperatures typically range between -8 °C (18 °F) and 21 °C (69 °F) through the year, but rarely can drop to -30 °C (-22 °F) or can rise to as high as 37 °C (99 °F).The average annual precipitation amounts to about 465 mm (18.3 inches) and receives 95 rainy days on the 1 mm (0.04 inches) threshold annually.Helena Valley Northwest enjoys an average of 3160 hours of sunshine throughout the year, and daylight varies from 8 hours 35 minutes to 15 hours 46 minutes per day.

Monthly average temperatures in Helena Valley Northwest, Montana, United States §

The warmest months in Helena Valley Northwest are June, July and August, with daily mean temperatures ranging from 16 to 21 °C (60 - 69 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -8 to -4 °C (18 - 25 °F) throughout the day. On average each year, Helena Valley Northwest experiences 58 days above 25 °C (77.0 °F) and 165 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Helena Valley Northwest, Montana, 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 6°C
(44°F)		 14°C
(57°F)		 19°C
(66°F)		 25°C
(78°F)		 28°C
(83°F)		 37°C
(98°F)		 36°C
(97°F)		 37°C
(99°F)		 33°C
(92°F)		 28°C
(82°F)		 20°C
(69°F)		 17°C
(63°F)
Mean maximum 5°C
(41°F)		 8°C
(47°F)		 14°C
(57°F)		 21°C
(71°F)		 26°C
(80°F)		 29°C
(84°F)		 34°C
(94°F)		 35°C
(94°F)		 32°C
(89°F)		 23°C
(74°F)		 15°C
(59°F)		 9°C
(49°F)
Average high -1°C
(30°F)		 -3°C
(27°F)		 5°C
(42°F)		 10°C
(50°F)		 16°C
(62°F)		 22°C
(72°F)		 29°C
(84°F)		 28°C
(82°F)		 21°C
(70°F)		 11°C
(53°F)		 5°C
(41°F)		 0°C
(33°F)
Daily mean -6°C
(22°F)		 -8°C
(18°F)		 -1°C
(31°F)		 4°C
(39°F)		 10°C
(51°F)		 16°C
(60°F)		 21°C
(69°F)		 20°C
(67°F)		 14°C
(57°F)		 5°C
(41°F)		 -0°C
(32°F)		 -4°C
(25°F)
Average low -10°C
(14°F)		 -13°C
(9°F)		 -6°C
(22°F)		 -2°C
(28°F)		 4°C
(40°F)		 9°C
(48°F)		 12°C
(54°F)		 12°C
(53°F)		 7°C
(45°F)		 -0°C
(32°F)		 -4°C
(25°F)		 -8°C
(18°F)
Mean minimum -23°C
(-10°F)		 -26°C
(-14°F)		 -19°C
(-2°F)		 -11°C
(13°F)		 -3°C
(28°F)		 3°C
(38°F)		 6°C
(44°F)		 7°C
(44°F)		 -1°C
(31°F)		 -10°C
(15°F)		 -13°C
(8°F)		 -19°C
(-2°F)
Minimum -29°C
(-20°F)		 -30°C
(-22°F)		 -30°C
(-21°F)		 -15°C
(5°F)		 -5°C
(23°F)		 2°C
(35°F)		 4°C
(39°F)		 4°C
(39°F)		 -4°C
(25°F)		 -19°C
(-2°F)		 -17°C
(2°F)		 -25°C
(-12°F)

Compare climate in Helena Valley Northwest with other places

Compare temperature, precipitation, sunshine, UV index in Helena Valley Northwest, Montana, United States with other places around the world.

Monthly average precipitation in Helena Valley Northwest, Montana, United States §

Helena Valley Northwest usually has the most precipitation in April, May and June, with an average of 11 rainy days and 67 mm (2.6 inches) of precipitation per month.The driest months in Helena Valley Northwest are January, July and August. On average, 19 mm (0.8 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Helena Valley Northwest, Montana, 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) 19 (0.7) 44 (1.7) 30 (1.2) 59 (2.3) 64 (2.5) 78 (3.1) 17 (0.7) 23 (0.9) 37 (1.5) 35 (1.4) 29 (1.1) 30 (1.2)
Average precipitation days (≥ 1 mm) 6 12 8 11 13 9 4 3 6 8 7 8

Monthly sunshine hours in Helena Valley Northwest, Montana, United States §

The sunniest months in Helena Valley Northwest are June, July and August, when the sun shines an average of 12 hours 0 minutes a day.Least sunny months in Helena Valley Northwest: January, February and December receive an average of 5 hours 35 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Helena Valley Northwest, Montana, 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 150 180 264 278 307 356 399 349 274 233 188 177
Mean daily daylight hours 9h 1m 10h 19m 11h 57m 13h 37m 15h 3m 15h 46m 15h 22m 14h 5m 12h 29m 10h 49m 9h 21m 8h 35m

Solar UV radiation in Helena Valley Northwest, Montana, United States §

Helena Valley Northwest experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 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 Helena Valley Northwest UV Index data.

Average daily maximum UV levels by month for Helena Valley Northwest, Montana, 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) 3 4 6 8 9 10 10 9 8 5 3 2