Boulder County Climate

Boulder County, Colorado

JanFebMarAprMayJunJulAugSepOctNovDec44.0°AVG °F

Avg Annual Temp

44.0°F

Annual Precip

22.6"

Annual Snowfall

96.0"

Extreme Heat Days

16.939999999999998

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
1.2"
1.3"
2.2"
3.2"
3.0"
1.9"
2.2"
2.1"
1.8"
1.5"
1.3"
1.1"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring35°49°8.3"Summer59°65°6.1"Fall35°56°4.7"Winter27°28°3.5"20°40°60°80°100°

National Comparison

Warmer than 10% of US counties
Wetter than 18% of US counties
More seasonal variation than 23% of US counties

Climate Profile

About Boulder County Weather

Boulder: Mountain cool on the Front Range

Boulder County averages 44°F annually, running 2 degrees cooler than the U.S. median of 46°F. With 22.6 inches of precipitation and only 17 extreme heat days per year, Boulder represents a cooler, wetter mountain climate despite Front Range proximity.

Colorado's cool alpine counties

At 44°F, Boulder ranks among Colorado's coolest counties, sitting 2 degrees below the state average of 46°F. Elevation and mountain terrain create a distinctly cooler pocket on the Front Range.

Mountain cool beats plains warmth

Boulder (44°F) runs 6.8 degrees cooler than neighboring Adams County (50.7°F) and 9.5 degrees cooler than Bent County (54.6°F). The elevation divide between mountain and plains creates dramatic climate contrasts across a short distance.

Snowy winters, cool summers

Summer temperatures average just 62.2°F while winters drop to 27.3°F, with only 17 days per year reaching 90°F. Annual snowfall of 95.9 inches makes Boulder Colorado's snowiest county on this list, creating a genuine alpine winter.

Heavy snow, minimal cooling needs

With nearly 96 inches of annual snowfall and consistently cool summers, residents prioritize winter-grade heating, insulation, and snow removal over air conditioning. Spring and summer outdoor work stretches short; winter preparation and avalanche awareness dominate the calendar in higher areas.

Frequently Asked Questions

What is the average temperature in Boulder County?
The average annual temperature in Boulder County, CO is 44.0°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Boulder County get?
Boulder County receives an average of 22.6 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Boulder County?
Yes, Boulder County receives an average of 96.0 inches of snowfall per year according to NOAA climate normals.
How hot does Boulder County get in summer?
The average summer temperature (June-August) in Boulder County is 62.2°F. The county experiences an average of 16.939999999999998 days per year above 90°F.
How cold are winters in Boulder County?
The average winter temperature (December-February) in Boulder County is 27.3°F. January, typically the coldest month, averages 27.0°F.

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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.

Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

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