Climateby Month

Great Falls, MT climate by month

NOAA 1991-2020 normals · 3,329 ft elevation

Great Falls has warm summers and cold and snowy winters. Highs peak at 84°F in July and fall to 35°F in January. Wet days are spread through the year, from about 7 to 12 a month. Normal snowfall is about 66 in a year. By our comfort score the best month is June.

Warmest month
84°F
July normal high
Coldest month
15°F
January normal low
Wet days a year
98
14.8 in of precipitation
Snow a year
66.1 in
normal snowfall

How warm is Great Falls?

Normal highs range from 35°F in January to 84°F in July.

0°20°40°60°80°100° January: normal high 35°F (2°C), low 15°F (-9°C) 35° 15° February: normal high 37°F (3°C), low 15°F (-9°C) March: normal high 46°F (8°C), low 22°F (-6°C) April: normal high 55°F (13°C), low 30°F (-1°C) May: normal high 65°F (18°C), low 38°F (3°C) June: normal high 73°F (23°C), low 46°F (8°C) July: normal high 84°F (29°C), low 51°F (11°C) 84° 51° August: normal high 83°F (28°C), low 50°F (10°C) September: normal high 72°F (22°C), low 43°F (6°C) October: normal high 57°F (14°C), low 33°F (1°C) November: normal high 44°F (7°C), low 24°F (-4°C) December: normal high 36°F (2°C), low 16°F (-9°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Great Falls?

June has the most wet days (about 12); the year brings about 15 in of precipitation.

January: 7 wet days February: 8 wet days March: 8 wet days April: 10 wet days May: 11 wet days June: 12 wet days 12 July: 7 wet days August: 7 wet days September: 7 wet days October: 7 wet days November: 7 wet days 7 December: 7 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 66.1 in a year, most of it in February.

January: 9.2 in of snow February: 10.1 in of snow 10.1 March: 10.1 in of snow April: 9.4 in of snow May: 1.9 in of snow June: 0.3 in of snow July: 0.0 in of snow 0.0 August: 0.3 in of snow September: 0.8 in of snow October: 5.2 in of snow November: 9.2 in of snow December: 9.6 in of snow JFMAMJJASOND

How humid is Great Falls?

Muggy days (dew point 65°F or higher) are rare in any month.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 0 muggy days August: 0 muggy days September: 0 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Great Falls International Airport, 4.3 mi WSW of the city center.

How much daylight?

Daylight ranges from about 8.5 hours in December to 15.9 hours in June.

January: 8.9 hours of daylight February: 10.3 hours of daylight March: 11.9 hours of daylight April: 13.7 hours of daylight May: 15.1 hours of daylight June: 15.9 hours of daylight 15.9 July: 15.5 hours of daylight August: 14.2 hours of daylight September: 12.6 hours of daylight October: 10.8 hours of daylight November: 9.3 hours of daylight December: 8.5 hours of daylight 8.5 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Great Falls, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 35°F15°F 0.6 in7 9.2 in 0 8.9 h
February 37°F15°F 0.6 in8 10.1 in 0 10.3 h
March 46°F22°F 0.7 in8 10.1 in 0 11.9 h
April 55°F30°F 1.7 in10 9.4 in 0 13.7 h
May 65°F38°F 2.4 in11 1.9 in 0 15.1 h
June 73°F46°F 2.7 in12 0.3 in 0 15.9 h
July 84°F51°F 1.2 in7 0.0 in 0 15.5 h
August 83°F50°F 1.2 in7 0.3 in 0 14.2 h
September 72°F43°F 1.3 in7 0.8 in 0 12.6 h
October 57°F33°F 1.1 in7 5.2 in 0 10.8 h
November 44°F24°F 0.7 in7 9.2 in 0 9.3 h
December 36°F16°F 0.5 in7 9.6 in 0 8.5 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Great Falls

By our comfort score, the best month is June.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 330216
Feb 370214
Mar 48229
Apr 58654
May 731461
Jun 781861
Jul 629310
Aug 61939
Sep 691432
Oct 55833
Nov 391211
Dec 320218

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Great Falls

The last spring frost typically comes around May 19, and the first fall frost around Sep 24, leaving 126 frost-free days in a typical year.

Frost and freeze dates for Great Falls
Typical date1 year in 10
Last spring frost (32°F)May 19after Jun 2
First fall frost (32°F)Sep 24before Sep 9
Last hard freeze (28°F)May 5after May 18
First hard freeze (28°F)Oct 3before Sep 20
Frost-free season126 daysunder 107 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Great Falls Intl Airport (USW00024143), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Montana.

Hottest and coldest readings, 1991-2020

The highest reading was 104°F (July 19, 2007, and 2 other days); the lowest was -35°F (February 2, 1996).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Great Falls

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Great Falls Intl Airport (USW00024143), 4.2 mi WSW of the city center, 3,664 ft (335 ft higher than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Great Falls International Airport (727750-24143), 4.3 mi WSW of the city center, 3,667 ft (338 ft higher than the city). Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error