Climateby Month

Big Sky, MT climate by month

NOAA 1991-2020 normals · 7,220 ft elevation

Big Sky has mild summers and very cold winters. Highs peak at 78°F in July and fall to 28°F in December. Wet days are spread through the year, from about 10 to 14 a month. By our comfort score the best months are June, July and September.

Warmest month
78°F
July normal high
Coldest month
9°F
January normal low
Wet days a year
141
23.3 in of precipitation
Hot days a year
1
90°F or hotter

How warm is Big Sky?

Normal highs range from 28°F in December to 78°F in July.

0°20°40°60°80° January: normal high 30°F (-1°C), low 9°F (-13°C) February: normal high 34°F (1°C), low 9°F (-13°C) March: normal high 42°F (6°C), low 17°F (-8°C) April: normal high 48°F (9°C), low 23°F (-5°C) May: normal high 58°F (14°C), low 30°F (-1°C) June: normal high 67°F (19°C), low 36°F (2°C) July: normal high 78°F (26°C), low 41°F (5°C) 78° 41° August: normal high 77°F (25°C), low 39°F (4°C) September: normal high 68°F (20°C), low 33°F (1°C) October: normal high 53°F (12°C), low 25°F (-4°C) November: normal high 37°F (3°C), low 16°F (-9°C) December: normal high 28°F (-2°C), low 9°F (-13°C) 28° 9° JFMAMJJASOND

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

How rainy is Big Sky?

June has the most wet days (about 14); the year brings about 23 in of precipitation.

January: 13 wet days February: 11 wet days March: 12 wet days April: 11 wet days May: 14 wet days June: 14 wet days 14 July: 10 wet days August: 11 wet days September: 10 wet days October: 10 wet days 10 November: 11 wet days December: 14 wet days JFMAMJJASOND

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

How humid is Big Sky?

Humidity data is not available for this location.

How much daylight?

Daylight ranges from about 8.8 hours in December to 15.6 hours in June.

January: 9.2 hours of daylight February: 10.4 hours of daylight March: 11.9 hours of daylight April: 13.5 hours of daylight May: 14.9 hours of daylight June: 15.6 hours of daylight 15.6 July: 15.2 hours of daylight August: 14.1 hours of daylight September: 12.5 hours of daylight October: 10.9 hours of daylight November: 9.5 hours of daylight December: 8.8 hours of daylight 8.8 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Big Sky, 1991-2020
MonthHighLowPrecip.Wet daysDaylight
January 30°F9°F 1.8 in13 9.2 h
February 34°F9°F 1.5 in11 10.4 h
March 42°F17°F 1.9 in12 11.9 h
April 48°F23°F 2.4 in11 13.5 h
May 58°F30°F 2.8 in14 14.9 h
June 67°F36°F 3.2 in14 15.6 h
July 78°F41°F 1.3 in10 15.2 h
August 77°F39°F 1.6 in11 14.1 h
September 68°F33°F 1.7 in10 12.5 h
October 53°F25°F 1.8 in10 10.9 h
November 37°F16°F 1.6 in11 9.5 h
December 28°F9°F 1.7 in14 8.8 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 Big Sky

By our comfort score, the best months are June, July and September.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 230628
Feb 280621
Mar 400512
Apr 50275
May 691281
Jun 771890
Jul 781741
Aug 761860
Sep 762050
Oct 50654
Nov 290618
Dec 220629

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. Comfortable days here are judged by temperature only (no humidity station nearby). How the score works.

Frost dates in Big Sky

Frost dates are not available for this location (no suitable station).

Hottest and coldest readings, 1991-2020

The highest reading was 95°F (July 13, 2002, and 1 other day); the lowest was -39°F (January 29, 1991).

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

Near Big Sky

Similar climates elsewhere

Where the numbers come from

  • Temperature and rain: Big Sky 2WNW (USC00240775), 2.1 mi ESE of the city center, 6,590 ft (630 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Not available for this location: snowfall, snow depth, frost dates, humidity and wind by hour, cloud cover and daily humidity and wind (no station close enough or similar enough in elevation).

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