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Monthly climate in Lewistown, Montana, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Lewistown features a humid continental climate (Dfb).Temperatures typically range between -8 °C (18 °F) and 20 °C (69 °F) through the year, but rarely can drop to -34 °C (-30 °F) or can rise to as high as 36 °C (97 °F).The average annual precipitation amounts to about 553 mm (21.8 inches) and receives 112 rainy days on the 1 mm (0.04 inches) threshold annually.Lewistown enjoys an average of 3171 hours of sunshine throughout the year, and daylight varies from 8 hours 33 minutes to 15 hours 49 minutes per day.

Monthly average temperatures in Lewistown, Montana, United States §

The warmest months in Lewistown are June, July and August, with daily mean temperatures ranging from 16 to 20 °C (61 - 69 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -8 to -3 °C (18 - 27 °F) throughout the day. On average each year, Lewistown experiences 51 days above 25 °C (77.0 °F) and 154 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Lewistown, 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 10°C
(51°F)		 14°C
(57°F)		 19°C
(67°F)		 26°C
(80°F)		 27°C
(81°F)		 36°C
(96°F)		 36°C
(97°F)		 36°C
(97°F)		 34°C
(94°F)		 28°C
(82°F)		 21°C
(71°F)		 17°C
(62°F)
Mean maximum 9°C
(48°F)		 10°C
(51°F)		 16°C
(60°F)		 23°C
(73°F)		 25°C
(77°F)		 28°C
(83°F)		 34°C
(94°F)		 34°C
(93°F)		 31°C
(89°F)		 24°C
(75°F)		 17°C
(62°F)		 12°C
(54°F)
Average high 0°C
(33°F)		 -3°C
(27°F)		 5°C
(42°F)		 9°C
(48°F)		 15°C
(60°F)		 22°C
(72°F)		 28°C
(82°F)		 27°C
(80°F)		 20°C
(69°F)		 11°C
(52°F)		 5°C
(42°F)		 1°C
(34°F)
Daily mean -4°C
(25°F)		 -8°C
(18°F)		 0°C
(32°F)		 3°C
(38°F)		 10°C
(50°F)		 16°C
(61°F)		 20°C
(69°F)		 19°C
(67°F)		 14°C
(57°F)		 5°C
(42°F)		 1°C
(34°F)		 -3°C
(27°F)
Average low -8°C
(18°F)		 -12°C
(10°F)		 -5°C
(24°F)		 -2°C
(29°F)		 4°C
(40°F)		 9°C
(49°F)		 13°C
(55°F)		 12°C
(54°F)		 8°C
(46°F)		 0°C
(32°F)		 -4°C
(26°F)		 -7°C
(19°F)
Mean minimum -23°C
(-9°F)		 -27°C
(-17°F)		 -18°C
(1°F)		 -13°C
(9°F)		 -2°C
(28°F)		 4°C
(39°F)		 7°C
(44°F)		 6°C
(43°F)		 -1°C
(31°F)		 -11°C
(13°F)		 -17°C
(3°F)		 -20°C
(-4°F)
Minimum -31°C
(-24°F)		 -34°C
(-30°F)		 -31°C
(-24°F)		 -20°C
(-4°F)		 -6°C
(21°F)		 3°C
(37°F)		 5°C
(41°F)		 2°C
(37°F)		 -3°C
(28°F)		 -17°C
(1°F)		 -25°C
(-13°F)		 -31°C
(-24°F)

Compare climate in Lewistown with other places

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

Monthly average precipitation in Lewistown, Montana, United States §

Lewistown usually has the most precipitation in April, May and June, with an average of 14 rainy days and 80 mm (3.2 inches) of precipitation per month.The driest months in Lewistown are January, March and July. On average, 28 mm (1.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Lewistown, 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) 25 (1.0) 43 (1.7) 29 (1.2) 76 (3.0) 84 (3.3) 80 (3.2) 30 (1.2) 31 (1.2) 45 (1.8) 45 (1.8) 34 (1.3) 31 (1.2)
Average precipitation days (≥ 1 mm) 6 11 9 14 16 12 7 6 6 11 7 7

Monthly sunshine hours in Lewistown, Montana, United States §

The sunniest months in Lewistown are June, July and August, when the sun shines an average of 11 hours 59 minutes a day.Least sunny months in Lewistown: January, November and December receive an average of 5 hours 38 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Lewistown, 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 153 190 267 266 315 361 395 346 269 238 187 178
Mean daily daylight hours 8h 58m 10h 18m 11h 57m 13h 38m 15h 5m 15h 49m 15h 25m 14h 7m 12h 29m 10h 48m 9h 19m 8h 33m

Solar UV radiation in Lewistown, Montana, United States §

Lewistown 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 Lewistown UV Index data.

Average daily maximum UV levels by month for Lewistown, 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) 2 4 5 8 9 10 10 9 8 5 3 2