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Weather & Climate in Boulder, CO
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Boulder experiences four distinct seasons with an average annual temperature of 47°F (8°C). Winters average 25°F in January while summers reach 71°F in July. The area gets 323 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 23.7 inches (drier than the 38-inch national average). The area receives 45.4 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 49. 58% of days have good air quality. The city sits at an elevation of 5,266 feet.
Temperature
25°F Jan (-4°C)
71°F Jul (22°C)
| Annual Average | 47.2°F |
| 13% below US avg | |
| January Average | 25°F (-4°C) |
| July Average | 71°F (22°C) |
| Sunny Days | 323 days/yr |
Geography
| Elevation | 5,266 ft (1,605 m) |
| Area | 25.7 sq mi (66.5 km²) |
| Population Density | 3,954/sq mi |
| Coordinates | 40.0244°N, 105.2513°W |
| Timezone | America/Denver |
| County | Boulder County County |
| Nearest Airport | Northern Colorado Regional (FNL) 32 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 49.0 |
| Rating | Good |
| Good Days % | 57.9% |
| Unhealthy Days | 10 |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 90.7 / 100 |
| Social Vulnerability | 11.4 / 100 |
| Community Resilience | 91.2 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Earthquake | Relatively Low |
| Wildfire | Relatively High |
| Flood | Relatively Moderate |
| Hail | Relatively High |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively High |
| Lightning | Very High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Moderate |
| Volcano | Very Low |
| Avalanche | Relatively High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
24 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.0.
| Dec 25, 1994 | 9 km NE of Larkspur, Colorado | M4.0 | 90 km | 10 km |
| Dec 23, 1995 | 7 km WNW of Rock Creek Park, Colorado | M3.5 | 147 km | 5 km |
| Apr 10, 2011 | 12 km N of Oak Creek, Colorado | M3.4 | 149 km | 5 km |
| Jan 18, 1997 | 8 km SE of Westcreek, Colorado | M3.3 | 104 km | 5 km |
| Jun 1, 2014 | 9 km NNW of Kersey, Colorado | M3.2 | 74 km | 1 km |
| Jul 22, 2001 | 6 km WNW of Woodland Park, Colorado | M3.1 | 112 km | 5 km |
| Feb 7, 2000 | 19 km NE of Steamboat Springs, Colorado | M3.0 | 136 km | 5 km |
| Sep 12, 1990 | 13 km NW of Silverthorne, Colorado | M3.0 | 89 km | 5 km |
| Feb 26, 2008 | 29 km WNW of Westcreek, Colorado | M2.9 | 85 km | 2 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.9 | 104 km | 5 km |
| Mar 30, 2019 | 7 km NE of Greeley, Colorado | M2.9 | 72 km | 6 km |
| Apr 30, 2008 | 3 km SW of Steamboat Springs, Colorado | M2.8 | 145 km | 5 km |
| Dec 31, 1995 | 6 km WNW of Rock Creek Park, Colorado | M2.8 | 148 km | 5 km |
| Jul 30, 2000 | 7 km SW of Steamboat Springs, Colorado | M2.8 | 147 km | 5 km |
| Jun 21, 2018 | 16 km SSW of Walden, Colorado | M2.7 | 114 km | 2 km |
| Feb 8, 2007 | 6 km S of Steamboat Springs, Colorado | M2.7 | 143 km | 5 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.7 | 104 km | 5 km |
| Apr 18, 1998 | 8 km SE of Westcreek, Colorado | M2.7 | 104 km | 5 km |
| Jun 13, 2025 | 7 km SE of Erie, Colorado | M2.7 | 23 km | 9 km |
| May 28, 2019 | 1 km ENE of Gypsum, Colorado | M2.6 | 150 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
625 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 1 fatality, 159 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 4, 2015 | EF3 | 29 km | 6.7 mi | 0 |
| May 22, 2008 | EF3 | 48 km | 38.7 mi | 1 |
| Jun 15, 1988 | EF3 | 43 km | 2.5 mi | 0 |
| Jun 12, 1982 | EF3 | 66 km | 3.0 mi | 0 |
| May 18, 1975 | EF3 | 51 km | 4.1 mi | 0 |
| May 15, 1952 | EF3 | 67 km | 7.4 mi | 0 |
| Jun 7, 2021 | EF2 | 32 km | 7.5 mi | 0 |
| May 7, 2016 | EF2 | 95 km | 8.8 mi | 0 |
| Jul 31, 1996 | EF2 | 77 km | 5.0 mi | 0 |
| Jul 13, 1996 | EF2 | 77 km | 12.0 mi | 0 |
| Jun 9, 1990 | EF2 | 81 km | 23.0 mi | 0 |
| Jun 15, 1988 | EF2 | 43 km | 0.5 mi | 0 |
| Jun 5, 1988 | EF2 | 24 km | 2.0 mi | 0 |
| Jun 5, 1988 | EF2 | 18 km | 0.5 mi | 0 |
| Jul 7, 1987 | EF2 | 86 km | 5.0 mi | 0 |
| Jul 2, 1987 | EF2 | 47 km | 1.0 mi | 0 |
| Jun 20, 1987 | EF2 | 61 km | 1.0 mi | 0 |
| Jun 8, 1986 | EF2 | 45 km | 1.1 mi | 0 |
| Jun 8, 1986 | EF2 | 60 km | 2.0 mi | 0 |
| Jul 19, 1985 | EF2 | 64 km | 0.5 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: CAMERON PEAK (208,910 acres, 2020).
| Year | Name | Acres Burned | Distance |
| 2020 | CAMERON PEAK | 208,910 | 71 km |
| 2020 | EAST TROUBLESOME | 188,924 | 67 km |
| 2002 | HAYMAN | 129,417 | 90 km |
| 2012 | HIGH PARK | 90,769 | 71 km |
| 2020 | WILLIAMS FORK | 14,679 | 66 km |
| 1996 | BUFFALO CREEK | 11,690 | 72 km |
| 2000 | BOBCAT | 10,444 | 50 km |
| 2020 | CALWOOD | 9,836 | 16 km |
| 2000 | HIGH MEADOWS | 9,607 | 70 km |
| 2004 | PICNIC ROCK | 9,014 | 77 km |
| 2001 | MVD PSFRXASST 4 | 7,375 | 89 km |
| 2021 | MARSHALL | 6,286 | 9 km |
| 2010 | FOURMILE CANYON | 5,865 | 12 km |
| 2002 | BIG ELK | 4,348 | 32 km |
| 2012 | LOWER NORTH FORK FIRE | 3,436 | 64 km |
| 2003 | OVERLAND | 3,232 | 15 km |
| 2009 | OLD STAGE | 3,160 | 8 km |
| 2011 | CRYSTAL FIRE | 2,855 | 60 km |
| 2002 | SCHOONOVER | 2,821 | 88 km |
| 2012 | FERN LAKE | 2,549 | 51 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 25°F (-4°C) | 0.6 in | Coldest, Driest |
| February | 33°F (1°C) | 0.6 in | |
| March | 39°F (4°C) | 1.7 in | |
| April | 46°F (8°C) | 2.3 in | |
| May | 56°F (13°C) | 2.7 in | Wettest |
| June | 65°F (18°C) | 1.9 in | |
| July | 71°F (22°C) | 1.9 in | Warmest |
| August | 69°F (21°C) | 1.6 in | |
| September | 61°F (16°C) | 1.6 in | |
| October | 50°F (10°C) | 1.2 in | |
| November | 37°F (3°C) | 1.2 in | |
| December | 31°F (-0°C) | 0.7 in |
Boulder has a seasonal temperature swing of 46°F / from 25°F in January to 71°F in July. Total annual precipitation is 17.9 inches, with May being the wettest month (2.7") and January the driest (0.6").