Weather & Climate in West Alton, MO
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
West Alton enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 30°F in January while summers reach 78°F in July. Annual precipitation totals 41.9 inches. The area receives 16.6 inches of snow annually, a moderate snowfall amount. The city sits at an elevation of 433 feet.
Temperature
30°F Jan (-1°C)
78°F Jul (26°C)
| Annual Average | 55.7°F |
| 3% above US avg | |
| January Average | 30°F (-1°C) |
| July Average | 78°F (26°C) |
Geography
| Elevation | 433 ft (132 m) |
| Area | 28.8 sq mi (74.6 km²) |
| Population Density | 18/sq mi |
| Coordinates | 38.8653°N, 90.2225°W |
| Timezone | America/Chicago |
| Nearest Airport | St Louis Regional (ALN) 10 miles away |
Precipitation & Snow
Air Quality
Earthquake History
34 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.9.
| Jun 7, 2011 | 18 km NNW of Potosi, Missouri | M3.9 | 106 km | 21 km |
| Mar 2, 1990 | 9 km NW of Vernon, Illinois | M3.4 | 91 km | 0 km |
| Aug 27, 1993 | 5 km SSE of Olympian Village, Missouri | M3.3 | 88 km | 22 km |
| Jan 29, 1993 | 7 km WNW of Brownstown, Illinois | M3.2 | 105 km | 5 km |
| Apr 6, 1994 | 2 km NE of Tamaroa, Illinois | M3.2 | 118 km | 15 km |
| Oct 24, 1990 | 5 km ENE of Woodlawn, Illinois | M3.2 | 123 km | 1 km |
| Jul 1, 2017 | 9 km SSE of Mulberry Grove, Illinois | M3.1 | 86 km | 17 km |
| Feb 28, 1994 | 5 km NW of Harrison, Illinois | M3.0 | 137 km | 5 km |
| May 18, 2006 | 9 km SSE of De Soto, Missouri | M2.9 | 94 km | 6 km |
| Sep 5, 2004 | 3 km WNW of Saint Peter, Illinois | M2.9 | 115 km | 33 km |
| Sep 5, 1995 | 3 km N of Woodlawn, Illinois | M2.9 | 117 km | 4 km |
| Jul 8, 2003 | 1 km N of Leasburg, Missouri | M2.9 | 126 km | 4 km |
| Apr 29, 2022 | 1 km SSW of Peerless Park, Missouri | M2.8 | 45 km | 8 km |
| Mar 28, 2024 | 1 km NNE of Germantown, Illinois | M2.8 | 68 km | 24 km |
| Jul 31, 1995 | 8 km SSW of Caledonia, Missouri | M2.8 | 140 km | 5 km |
| Aug 26, 1992 | 5 km W of Frohna, Missouri | M2.8 | 144 km | 2 km |
| May 5, 2008 | 3 km SSE of Fenton, Missouri | M2.8 | 45 km | 19 km |
| Sep 13, 1997 | 3 km SSE of Darmstadt, Illinois | M2.8 | 78 km | 16 km |
| Nov 12, 1996 | 15 km SSE of Olympian Village, Missouri | M2.7 | 98 km | 5 km |
| Jul 22, 1998 | 12 km NE of Mine La Motte, Missouri | M2.7 | 131 km | 11 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
635 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 60 fatalities, 1,086 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Nov 17, 2013 | EF4 | 83 km | 10.6 mi | 2 |
| Apr 22, 2011 | EF4 | 27 km | 21.3 mi | 0 |
| Apr 3, 1981 | EF4 | 18 km | 11.9 mi | 0 |
| Jan 24, 1967 | EF4 | 35 km | 25.0 mi | 3 |
| Feb 10, 1959 | EF4 | 50 km | 23.9 mi | 21 |
| Feb 24, 1956 | EF4 | 76 km | 77.6 mi | 6 |
| Dec 10, 2021 | EF3 | 19 km | 4.2 mi | 6 |
| Dec 10, 2021 | EF3 | 66 km | 24.8 mi | 1 |
| Dec 1, 2018 | EF3 | 94 km | 12.5 mi | 0 |
| May 31, 2013 | EF3 | 10 km | 10.6 mi | 0 |
| May 31, 2013 | EF3 | 50 km | 31.7 mi | 0 |
| Apr 19, 2011 | EF3 | 73 km | 4.3 mi | 0 |
| Dec 31, 2010 | EF3 | 47 km | 6.7 mi | 1 |
| Mar 13, 2006 | EF3 | 95 km | 6.0 mi | 0 |
| Mar 11, 2006 | EF3 | 83 km | 5.1 mi | 0 |
| Jun 1, 1999 | EF3 | 70 km | 10.0 mi | 1 |
| Nov 15, 1988 | EF3 | 33 km | 9.0 mi | 0 |
| Nov 15, 1988 | EF3 | 42 km | 1.0 mi | 0 |
| Apr 29, 1984 | EF3 | 61 km | 8.0 mi | 0 |
| May 1, 1983 | EF3 | 27 km | 16.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 30°F (-1°C) | 2.5 in | Coldest |
| February | 35°F (1°C) | 2.5 in | Driest |
| March | 44°F (7°C) | 3.5 in | |
| April | 56°F (13°C) | 4.9 in | |
| May | 66°F (19°C) | 5.5 in | Wettest |
| June | 75°F (24°C) | 3.4 in | |
| July | 78°F (26°C) | 4.0 in | Warmest |
| August | 77°F (25°C) | 3.3 in | |
| September | 70°F (21°C) | 3.4 in | |
| October | 58°F (14°C) | 2.9 in | |
| November | 45°F (7°C) | 3.4 in | |
| December | 35°F (2°C) | 2.6 in |
West Alton has a seasonal temperature swing of 48°F / from 30°F in January to 78°F in July. Total annual precipitation is 41.9 inches, with May being the wettest month (5.5") and February the driest (2.5").