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Weather & Climate in Johnstown, CO
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Johnstown experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 31°F in January while summers reach 76°F in July. The area gets 316 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 14.7 inches (drier than the 38-inch national average). The area receives 34.9 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 4,840 feet.
Temperature
31°F Jan (-1°C)
76°F Jul (24°C)
| Annual Average | 52.1°F |
| 4% below US avg | |
| January Average | 31°F (-1°C) |
| July Average | 76°F (24°C) |
| Sunny Days | 316 days/yr |
Geography
| Elevation | 4,840 ft (1,475 m) |
| Area | 13.6 sq mi (35.2 km²) |
| Population Density | 1,160/sq mi |
| Coordinates | 40.3072°N, 104.9112°W |
| Timezone | America/Denver |
| County | Weld County County |
| Nearest Airport | Northern Colorado Regional (FNL) 11 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 89.2 / 100 |
| Social Vulnerability | 11.4 / 100 |
| Community Resilience | 56.2 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Earthquake | Relatively Low |
| Wildfire | Relatively Low |
| Flood | Relatively Moderate |
| Hail | Relatively High |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
| Volcano | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
14 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 | 113 km | 10 km |
| Jan 18, 1997 | 8 km SE of Westcreek, Colorado | M3.3 | 135 km | 5 km |
| Jun 1, 2014 | 9 km NNW of Kersey, Colorado | M3.2 | 31 km | 1 km |
| Jul 22, 2001 | 6 km WNW of Woodland Park, Colorado | M3.1 | 144 km | 5 km |
| Sep 12, 1990 | 13 km NW of Silverthorne, Colorado | M3.0 | 129 km | 5 km |
| Feb 26, 2008 | 29 km WNW of Westcreek, Colorado | M2.9 | 124 km | 2 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.9 | 135 km | 5 km |
| Mar 30, 2019 | 7 km NE of Greeley, Colorado | M2.9 | 29 km | 6 km |
| Jun 21, 2018 | 16 km SSW of Walden, Colorado | M2.7 | 127 km | 2 km |
| Jan 19, 1997 | 8 km SE of Westcreek, Colorado | M2.7 | 135 km | 5 km |
| Apr 18, 1998 | 8 km SE of Westcreek, Colorado | M2.7 | 135 km | 5 km |
| Jun 13, 2025 | 7 km SE of Erie, Colorado | M2.7 | 34 km | 9 km |
| Aug 23, 2016 | 2 km SSE of Eaton, Colorado | M2.6 | 28 km | 10 km |
| Jun 23, 2014 | 6 km NNE of Kersey, Colorado | M2.5 | 35 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
739 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 2 fatalities, 199 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 4, 2015 | EF3 | 16 km | 6.7 mi | 0 |
| May 22, 2008 | EF3 | 16 km | 38.7 mi | 1 |
| Jun 15, 1988 | EF3 | 64 km | 2.5 mi | 0 |
| Jun 12, 1982 | EF3 | 63 km | 3.0 mi | 0 |
| Jul 16, 1979 | EF3 | 96 km | 8.8 mi | 1 |
| May 18, 1975 | EF3 | 59 km | 4.1 mi | 0 |
| Apr 23, 1960 | EF3 | 85 km | 17.2 mi | 0 |
| May 15, 1952 | EF3 | 29 km | 7.4 mi | 0 |
| Jun 7, 2021 | EF2 | 19 km | 7.5 mi | 0 |
| Jun 12, 2017 | EF2 | 82 km | 15.0 mi | 0 |
| May 7, 2016 | EF2 | 64 km | 8.8 mi | 0 |
| May 22, 2008 | EF2 | 83 km | 25.1 mi | 0 |
| Jul 31, 1996 | EF2 | 36 km | 5.0 mi | 0 |
| Jul 30, 1996 | EF2 | 80 km | 0.5 mi | 0 |
| Jul 13, 1996 | EF2 | 71 km | 12.0 mi | 0 |
| May 30, 1996 | EF2 | 89 km | 1.0 mi | 0 |
| Jun 9, 1990 | EF2 | 46 km | 23.0 mi | 0 |
| Jun 15, 1988 | EF2 | 64 km | 0.5 mi | 0 |
| Jun 5, 1988 | EF2 | 35 km | 2.0 mi | 0 |
| Jun 5, 1988 | EF2 | 42 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 | 64 km |
| 2020 | EAST TROUBLESOME | 188,924 | 92 km |
| 2012 | HIGH PARK | 90,769 | 54 km |
| 2000 | BOBCAT | 10,444 | 38 km |
| 2020 | CALWOOD | 9,836 | 39 km |
| 2004 | PICNIC ROCK | 9,014 | 53 km |
| 2024 | HAPPY JACK | 6,585 | 99 km |
| 2021 | MARSHALL | 6,286 | 45 km |
| 2010 | FOURMILE CANYON | 5,865 | 49 km |
| 2002 | UNNAMED | 5,258 | 85 km |
| 2002 | BIG ELK | 4,348 | 43 km |
| 2021 | BIJOU | 3,485 | 80 km |
| 2012 | LOWER NORTH FORK FIRE | 3,436 | 98 km |
| 2003 | OVERLAND | 3,232 | 42 km |
| 2004 | ROSETTA LANE | 3,164 | 80 km |
| 2009 | OLD STAGE | 3,160 | 40 km |
| 2011 | CRYSTAL FIRE | 2,855 | 44 km |
| 2012 | FERN LAKE | 2,549 | 64 km |
| 2020 | SUNDAY FIRE | 2,204 | 32 km |
| 2017 | CATTLE DRIVE | 2,200 | 66 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-1°C) | 0.5 in | |
| February | 33°F (0°C) | 0.4 in | Driest |
| March | 40°F (5°C) | 1.4 in | |
| April | 48°F (9°C) | 1.9 in | |
| May | 57°F (14°C) | 2.6 in | Wettest |
| June | 67°F (19°C) | 1.9 in | |
| July | 76°F (24°C) | 1.7 in | Warmest |
| August | 70°F (21°C) | 1.4 in | |
| September | 61°F (16°C) | 1.4 in | |
| October | 50°F (10°C) | 1.0 in | |
| November | 37°F (3°C) | 0.9 in | |
| December | 29°F (-2°C) | 0.5 in | Coldest |
Johnstown has a seasonal temperature swing of 47°F / from 29°F in December to 76°F in July. Total annual precipitation is 15.6 inches, with May being the wettest month (2.6") and February the driest (0.4").