Boulder County Climate
Boulder County, Colorado
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
44.0°F
Annual Precip
22.6"
Annual Snowfall
95.9"
Extreme Heat Days
17
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
1,639
Favors cool-season crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Boulder County
Climate Verdict
Boulder County has a cool, averaging 44.0°F annually, semi-arid conditions with only 22.6 inches of annual precipitation, rare extreme heat with only 16.939999999999998 days above 90°F annually, heavy winter snowfall averaging 95.9 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 27.0°F. summers are pleasantly cool with July averaging 64.9°F. The 38°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Boulder County closely matches the Colorado statewide average temperature of 45.9°F, it is also noticeably wetter, receiving 6.5 inches more precipitation than the state average.
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
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.