Weather & Climate in Longmont, CO
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Longmont experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 29°F in January while summers reach 73°F in July. Annual precipitation totals 15.2 inches (drier than the 38-inch national average). The area receives 47.4 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 4,990 feet.
Temperature
29°F Jan (-1°C)
73°F Jul (23°C)
| Annual Average | 50.0°F |
| 7% below US avg | |
| January Average | 29°F (-1°C) |
| July Average | 73°F (23°C) |
Geography
| Elevation | 4,990 ft (1,521 m) |
| Area | 27.7 sq mi (71.6 km²) |
| Population Density | 3,382/sq mi |
| Coordinates | 40.1699°N, 105.1018°W |
| Timezone | America/Denver |
| County | Boulder County County |
| Nearest Airport | Northern Colorado Regional (FNL) 20 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
16 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 | 101 km | 10 km |
| Jan 18, 1997 | 8 km SE of Westcreek, Colorado | M3.3 | 119 km | 5 km |
| Jun 1, 2014 | 9 km NNW of Kersey, Colorado | M3.2 | 53 km | 1 km |
| Jul 22, 2001 | 6 km WNW of Woodland Park, Colorado | M3.1 | 128 km | 5 km |
| Feb 7, 2000 | 19 km NE of Steamboat Springs, Colorado | M3.0 | 141 km | 5 km |
| Sep 12, 1990 | 13 km NW of Silverthorne, Colorado | M3.0 | 108 km | 5 km |
| Feb 26, 2008 | 29 km WNW of Westcreek, Colorado | M2.9 | 104 km | 2 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.9 | 119 km | 5 km |
| Mar 30, 2019 | 7 km NE of Greeley, Colorado | M2.9 | 52 km | 6 km |
| Jun 21, 2018 | 16 km SSW of Walden, Colorado | M2.7 | 117 km | 2 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.7 | 119 km | 5 km |
| Apr 18, 1998 | 8 km SE of Westcreek, Colorado | M2.7 | 119 km | 5 km |
| Jun 13, 2025 | 7 km SE of Erie, Colorado | M2.7 | 21 km | 9 km |
| Aug 23, 2016 | 2 km SSE of Eaton, Colorado | M2.6 | 50 km | 10 km |
| Feb 9, 2000 | 21 km NNE of Steamboat Springs, Colorado | M2.5 | 148 km | 5 km |
| Jun 23, 2014 | 6 km NNE of Kersey, Colorado | M2.5 | 56 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
666 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 1 fatality, 161 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 4, 2015 | EF3 | 9 km | 6.7 mi | 0 |
| May 22, 2008 | EF3 | 31 km | 38.7 mi | 1 |
| Jun 15, 1988 | EF3 | 51 km | 2.5 mi | 0 |
| Jun 12, 1982 | EF3 | 62 km | 3.0 mi | 0 |
| May 18, 1975 | EF3 | 52 km | 4.1 mi | 0 |
| Apr 23, 1960 | EF3 | 96 km | 17.2 mi | 0 |
| May 15, 1952 | EF3 | 49 km | 7.4 mi | 0 |
| Jun 7, 2021 | EF2 | 17 km | 7.5 mi | 0 |
| May 7, 2016 | EF2 | 79 km | 8.8 mi | 0 |
| May 22, 2008 | EF2 | 93 km | 25.1 mi | 0 |
| Jul 31, 1996 | EF2 | 58 km | 5.0 mi | 0 |
| Jul 30, 1996 | EF2 | 98 km | 0.5 mi | 0 |
| Jul 13, 1996 | EF2 | 73 km | 12.0 mi | 0 |
| Jun 9, 1990 | EF2 | 62 km | 23.0 mi | 0 |
| Jun 15, 1988 | EF2 | 51 km | 0.5 mi | 0 |
| Jun 5, 1988 | EF2 | 22 km | 2.0 mi | 0 |
| Jun 5, 1988 | EF2 | 25 km | 0.5 mi | 0 |
| Jul 7, 1987 | EF2 | 67 km | 5.0 mi | 0 |
| Jul 2, 1987 | EF2 | 45 km | 1.0 mi | 0 |
| Jun 20, 1987 | EF2 | 61 km | 1.0 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 | 63 km |
| 2020 | EAST TROUBLESOME | 188,924 | 76 km |
| 2012 | HIGH PARK | 90,769 | 58 km |
| 2020 | WILLIAMS FORK | 14,679 | 84 km |
| 1996 | BUFFALO CREEK | 11,690 | 89 km |
| 2000 | BOBCAT | 10,444 | 38 km |
| 2020 | CALWOOD | 9,836 | 19 km |
| 2000 | HIGH MEADOWS | 9,607 | 88 km |
| 2004 | PICNIC ROCK | 9,014 | 62 km |
| 2021 | MARSHALL | 6,286 | 25 km |
| 2010 | FOURMILE CANYON | 5,865 | 28 km |
| 2002 | BIG ELK | 4,348 | 30 km |
| 2021 | BIJOU | 3,485 | 95 km |
| 2012 | LOWER NORTH FORK FIRE | 3,436 | 80 km |
| 2003 | OVERLAND | 3,232 | 22 km |
| 2004 | ROSETTA LANE | 3,164 | 100 km |
| 2009 | OLD STAGE | 3,160 | 18 km |
| 2011 | CRYSTAL FIRE | 2,855 | 47 km |
| 2012 | FERN LAKE | 2,549 | 52 km |
| 2020 | SUNDAY FIRE | 2,204 | 45 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 29°F (-1°C) | 0.6 in | Coldest |
| February | 32°F (0°C) | 0.6 in | |
| March | 42°F (5°C) | 1.2 in | |
| April | 48°F (9°C) | 2.0 in | Wettest |
| May | 57°F (14°C) | 2.0 in | |
| June | 67°F (20°C) | 1.8 in | |
| July | 73°F (23°C) | 1.7 in | Warmest |
| August | 71°F (22°C) | 2.0 in | |
| September | 63°F (17°C) | 1.3 in | |
| October | 50°F (10°C) | 1.0 in | |
| November | 39°F (4°C) | 0.8 in | |
| December | 30°F (-1°C) | 0.5 in | Driest |
Longmont has a seasonal temperature swing of 44°F / from 29°F in January to 73°F in July. Total annual precipitation is 15.2 inches, with April being the wettest month (2.0") and December the driest (0.5").