Boulder, MT

Climate overview — based on NOAA 1991-2020 normals from BOULDER, MT US.

BSk Semi-arid (cold) climate 6b USDA hardiness Zone 6b

Year-round temperatures (°F)

10° 30° 50° 70° 90° J F M A M J J A S O N D
Avg high Avg low

Climate summary

Boulder has an annual average temperature of 42.6°F with about 10.8 inches of precipitation per year. The warmest month is July (average high 82.5°F), and the coldest is December (average low 11.5°F). June is typically the wettest month (2.30 in) and February the driest (0.19 in).

Annual swing
42.9°F
warmest to coldest month
Heating need
8,094
Cooling need
12

Best time to visit Boulder

Full guide →

Climate change signal

All-time records →

51 of 366 (13.9%) of Boulder's all-time daily heat records have been set since 2015. If records were spread evenly across the station's history, only about 5% would fall in any given decade.

1940s
8
1950s
48
1960s
52
1970s
33
1980s
66
1990s
47
2000s
45
2010s
32
2020s
35

Bars: number of all-time daily heat records still standing that were set in each decade.

Monthly averages

Month Avg High Avg Low Avg Temp Precipitation Snow Rainy days
January 35.0°F 11.9°F 23.5°F 0.28 in 5
February 37.8°F 14.0°F 25.9°F 0.19 in 5
March 46.8°F 20.8°F 33.8°F 0.40 in 6
April 54.5°F 27.0°F 40.7°F 0.78 in 7
May 63.6°F 35.3°F 49.4°F 1.86 in 12
June 72.0°F 42.5°F 57.2°F 2.30 in 12
July 82.5°F 48.3°F 65.4°F 1.38 in 8
August 82.0°F 46.2°F 64.1°F 1.12 in 7
September 71.9°F 38.1°F 55.0°F 1.10 in 7
October 57.4°F 27.7°F 42.6°F 0.64 in 7
November 42.4°F 18.6°F 30.5°F 0.48 in 6
December 33.6°F 11.5°F 22.5°F 0.27 in 6

Climate twins of Boulder

Why these? →

The most climatically similar US cities at least 140 miles away (by monthly temperature + precipitation pattern).

Frost dates
Last spring / first fall frost
All-time records
Hottest, coldest, wettest
Planting calendar
What to plant, and when

Compare Boulder to another city