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Weather & Climate in Alton, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Alton experiences four distinct seasons with an average annual temperature of 47°F (8°C). Winters average 17°F in January while summers reach 73°F in July. The area gets 291 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 30.0 inches (drier than the 38-inch national average). The area receives 30.9 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,314 feet.
Temperature
17°F Jan (-8°C)
73°F Jul (23°C)
| Annual Average | 46.9°F |
| 13% below US avg | |
| January Average | 17°F (-8°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 291 days/yr |
Geography
| Elevation | 1,314 ft (401 m) |
| Area | 1.9 sq mi (4.8 km²) |
| Population Density | 707/sq mi |
| Coordinates | 42.9877°N, 96.0094°W |
| Timezone | America/Chicago |
| County | Plymouth County County |
| Nearest Airport | Sioux Gateway/Brig General Bud Day Field (SUX) 45 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 49.2 / 100 |
| Social Vulnerability | 26.2 / 100 |
| Community Resilience | 89.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.6.
| Feb 6, 1996 | 1 km N of Wausa, Nebraska | M3.6 | 136 km | 5 km |
| Jun 30, 2021 | 4 km E of Rembrandt, Iowa | M2.7 | 76 km | 10 km |
| Mar 6, 2024 | 6 km SSE of Santee, Nebraska | M2.5 | 148 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
647 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 6 fatalities, 175 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 16, 1992 | EF5 | 90 km | 16.0 mi | 1 |
| Oct 4, 2013 | EF4 | 73 km | 24.7 mi | 0 |
| Apr 9, 2011 | EF4 | 98 km | 3.2 mi | 0 |
| Jun 25, 2010 | EF4 | 51 km | 13.7 mi | 0 |
| Jul 28, 1986 | EF4 | 86 km | 52.5 mi | 0 |
| Jun 23, 1952 | EF4 | 29 km | 24.1 mi | 0 |
| Apr 9, 2011 | EF3 | 92 km | 10.1 mi | 0 |
| Apr 9, 2011 | EF3 | 94 km | 3.4 mi | 0 |
| Apr 9, 2011 | EF3 | 89 km | 29.4 mi | 0 |
| Jun 11, 2004 | EF3 | 80 km | 6.1 mi | 0 |
| Aug 7, 1994 | EF3 | 55 km | 4.5 mi | 0 |
| Jul 5, 1994 | EF3 | 77 km | 1.8 mi | 0 |
| Aug 3, 1981 | EF3 | 98 km | 12.8 mi | 0 |
| Sep 20, 1980 | EF3 | 72 km | 1.5 mi | 0 |
| May 8, 1979 | EF3 | 61 km | 0.1 mi | 0 |
| Jul 5, 1978 | EF3 | 43 km | 8.0 mi | 0 |
| Oct 1, 1971 | EF3 | 43 km | 11.2 mi | 0 |
| May 31, 1971 | EF3 | 54 km | 8.6 mi | 0 |
| May 31, 1971 | EF3 | 70 km | 8.0 mi | 0 |
| May 31, 1971 | EF3 | 26 km | 46.5 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: DEWEYS PASTURE (641 acres, 2008).
| Year | Name | Acres Burned | Distance |
| 2008 | DEWEYS PASTURE | 641 | 91 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 17°F (-8°C) | 0.6 in | Coldest, Driest |
| February | 23°F (-5°C) | 0.6 in | |
| March | 35°F (1°C) | 1.9 in | |
| April | 48°F (9°C) | 2.6 in | |
| May | 60°F (16°C) | 3.4 in | |
| June | 70°F (21°C) | 4.1 in | Wettest |
| July | 73°F (23°C) | 3.4 in | Warmest |
| August | 71°F (22°C) | 3.4 in | |
| September | 62°F (17°C) | 2.9 in | |
| October | 50°F (10°C) | 2.0 in | |
| November | 33°F (1°C) | 1.2 in | |
| December | 21°F (-6°C) | 0.8 in |
Alton has a seasonal temperature swing of 56°F / from 17°F in January to 73°F in July. Total annual precipitation is 26.9 inches, with June being the wettest month (4.1") and January the driest (0.6").