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Weather & Climate in St. Charles, MO
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
St. Charles enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 34°F in January while summers reach 77°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 42.0 inches. The area receives 3.2 inches of snow annually. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 226 feet.
Temperature
34°F Jan (1°C)
77°F Jul (25°C)
| Annual Average | 56.0°F |
| 4% above US avg | |
| January Average | 34°F (1°C) |
| July Average | 77°F (25°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 226 ft (69 m) |
| Area | 24.0 sq mi (62.2 km²) |
| Population Density | 2,818/sq mi |
| Coordinates | 38.6073°N, 76.9248°W |
| Timezone | America/Chicago |
| Nearest Airport | Ronald Reagan Washington Ntl (DCA) 18 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Earthquake History
42 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.8.
| Aug 23, 2011 | 11 km SSW of Mineral, Virginia | M5.8 | 118 km | 6 km |
| Aug 25, 2011 | 8 km SW of Mineral, Virginia | M4.5 | 117 km | 7 km |
| Aug 24, 2011 | 11 km SSW of Mineral, Virginia | M4.2 | 118 km | 0 km |
| Mar 15, 1991 | 7 km NNW of Goochland, Virginia | M3.8 | 129 km | 16 km |
| Jul 16, 2010 | 5 km NNW of Barnesville, Maryland | M3.6 | 84 km | 7 km |
| May 5, 2003 | Virginia | M3.6 | 142 km | 13 km |
| Aug 24, 2011 | 16 km NNW of Goochland, Virginia | M3.4 | 125 km | 0 km |
| Sep 1, 2011 | 7 km SSW of Mineral, Virginia | M3.4 | 114 km | 3 km |
| Sep 22, 2001 | 5 km E of Pantops, Virginia | M3.2 | 144 km | 0 km |
| Jan 30, 2012 | 9 km SSE of Louisa, Virginia | M3.1 | 118 km | 3 km |
| Jan 17, 2016 | 3 km NE of Ranson, West Virginia | M3.0 | 111 km | 5 km |
| Oct 2, 2010 | 10 km NNW of Ashland, Virginia | M3.0 | 99 km | 19 km |
| Oct 12, 2011 | 9 km S of Louisa, Virginia | M3.0 | 119 km | 4 km |
| Mar 26, 2012 | 13 km S of Louisa, Virginia | M3.0 | 121 km | 9 km |
| Aug 3, 1995 | 13 km N of Williamsburg, Virginia | M2.9 | 137 km | 1 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 147 km | 5 km |
| Aug 23, 2011 | 9 km SSW of Mineral, Virginia | M2.8 | 116 km | 0 km |
| Mar 15, 2015 | 6 km SW of Mineral, Virginia | M2.8 | 115 km | 5 km |
| Jan 14, 2025 | 1 km NNE of Wyndham, Virginia | M2.8 | 117 km | 0 km |
| Feb 19, 2012 | 12 km S of Louisa, Virginia | M2.7 | 120 km | 3 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
7 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 3.
| Year | Name | Category | Max Wind | Closest |
| 2014 | Arthur | Category 2 | 92 mph | 300 km |
| 2011 | Irene | Category 1 | 75 mph | 177 km |
| 2003 | Isabel | Category 1 | 75 mph | 223 km |
| 1999 | Floyd | Category 1 | — | 214 km |
| 1991 | Bob | Category 3 | 115 mph | 295 km |
| 1986 | Charley | Category 1 | 81 mph | 202 km |
| 1985 | Gloria | Category 2 | 98 mph | 212 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
431 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 10 fatalities, 416 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 28, 2002 | EF4 | 23 km | 38.0 mi | 3 |
| Sep 24, 2001 | EF4 | 92 km | 10.0 mi | 0 |
| Feb 24, 2016 | EF3 | 90 km | 30.3 mi | 0 |
| Sep 17, 2004 | EF3 | 77 km | 9.0 mi | 0 |
| Apr 28, 2002 | EF3 | 58 km | 18.0 mi | 0 |
| Sep 24, 2001 | EF3 | 36 km | 17.5 mi | 2 |
| Jul 19, 1996 | EF3 | 99 km | 2.2 mi | 0 |
| Oct 18, 1990 | EF3 | 97 km | 3.5 mi | 0 |
| Sep 5, 1979 | EF3 | 24 km | 17.9 mi | 1 |
| Jan 26, 1978 | EF3 | 35 km | 0.7 mi | 1 |
| Apr 1, 1973 | EF3 | 41 km | 9.8 mi | 0 |
| Nov 2, 1966 | EF3 | 73 km | 0.1 mi | 0 |
| Jun 9, 1961 | EF3 | 71 km | 0.1 mi | 0 |
| Sep 1, 2021 | EF2 | 39 km | 11.4 mi | 0 |
| May 3, 2021 | EF2 | 79 km | 4.4 mi | 0 |
| Nov 2, 2018 | EF2 | 85 km | 5.5 mi | 0 |
| Jul 23, 2017 | EF2 | 64 km | 2.4 mi | 0 |
| May 8, 2008 | EF2 | 59 km | 3.4 mi | 0 |
| Sep 17, 2004 | EF2 | 74 km | 8.0 mi | 0 |
| Sep 17, 2004 | EF2 | 72 km | 13.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: BESTPITCH (7,743 acres, 2017).
| Year | Name | Acres Burned | Distance |
| 2017 | BESTPITCH | 7,743 | 84 km |
| 2004 | RETAINING ECOLOGICAL HEALTH | 5,678 | 78 km |
| 2014 | BLACKWATER MARSH WUI BURNS FY14 | 5,433 | 79 km |
| 2005 | MARSH RX-FWS | 4,380 | 81 km |
| 2007 | GUINEA MARSH | 4,173 | 88 km |
| 2009 | DOCTORS CREEK | 3,686 | 87 km |
| 1999 | FB R O C I | 3,525 | 82 km |
| 2019 | MDBWR-FY19-RX-MDWHS SUPPORT | 3,197 | 80 km |
| 2011 | COMPARTMENT J | 2,775 | 80 km |
| 2005 | ISLAND CREEK | 2,729 | 88 km |
| 2004 | UNNAMED | 2,156 | 88 km |
| 1992 | UNNAMED | 2,038 | 84 km |
| 2005 | VEGETATION RESEARCH | 1,926 | 85 km |
| 2011 | THOROFARE | 1,850 | 84 km |
| 1987 | UNNAMED | 1,692 | 77 km |
| 2004 | ROBBINS FIRE | 1,612 | 81 km |
| 2004 | BLACKWATER HAZARD FUEL REDUCTION | 1,518 | 72 km |
| 2009 | BECKERS ISLAND | 1,398 | 81 km |
| 2022 | ELLIOTTS ISLAND | 1,324 | 89 km |
| 2006 | UNNAMED | 1,260 | 77 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 34°F (1°C) | 3.2 in | Coldest |
| February | 37°F (3°C) | 2.9 in | Driest |
| March | 45°F (7°C) | 3.6 in | |
| April | 55°F (13°C) | 3.2 in | |
| May | 64°F (18°C) | 3.9 in | |
| June | 72°F (22°C) | 3.6 in | |
| July | 77°F (25°C) | 3.9 in | Warmest |
| August | 75°F (24°C) | 4.1 in | Wettest |
| September | 69°F (20°C) | 3.7 in | |
| October | 57°F (14°C) | 3.3 in | |
| November | 48°F (9°C) | 3.4 in | |
| December | 39°F (4°C) | 3.2 in |
St. Charles has a seasonal temperature swing of 43°F / from 34°F in January to 77°F in July. Total annual precipitation is 42.0 inches, with August being the wettest month (4.1") and February the driest (2.9").