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Weather & Climate in Monmouth, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Monmouth experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 19°F in January while summers reach 73°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 36.7 inches. The area receives 30.3 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 744 feet.
Temperature
19°F Jan (-7°C)
73°F Jul (23°C)
| Annual Average | 47.9°F |
| 11% below US avg | |
| January Average | 19°F (-7°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 744 ft (227 m) |
| Area | 0.6 sq mi (1.5 km²) |
| Population Density | 196/sq mi |
| Coordinates | 42.0751°N, 90.8822°W |
| Timezone | America/Chicago |
| County | Jackson County County |
| Nearest Airport | Monticello Regional (MXO) 18 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 36.1 / 100 |
| Social Vulnerability | 15.9 / 100 |
| Community Resilience | 75.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1 earthquake (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.5.
| Sep 2, 1999 | 8 km W of Amboy, Illinois | M3.5 | 126 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
648 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 5 fatalities, 222 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 13, 1990 | EF4 | 48 km | 19.0 mi | 0 |
| Mar 29, 1981 | EF4 | 89 km | 5.1 mi | 0 |
| Aug 12, 1974 | EF4 | 58 km | 5.0 mi | 0 |
| Apr 11, 1965 | EF4 | 25 km | 91.5 mi | 1 |
| Apr 30, 1954 | EF4 | 72 km | 80.4 mi | 0 |
| Jun 1, 2007 | EF3 | 93 km | 15.8 mi | 0 |
| May 21, 2004 | EF3 | 78 km | 3.0 mi | 0 |
| Jul 27, 1995 | EF3 | 88 km | 20.0 mi | 0 |
| May 9, 1995 | EF3 | 55 km | 10.0 mi | 0 |
| Jun 19, 1993 | EF3 | 30 km | 14.0 mi | 0 |
| Jun 19, 1993 | EF3 | 66 km | 9.0 mi | 0 |
| Jul 13, 1992 | EF3 | 24 km | 5.0 mi | 0 |
| Mar 13, 1990 | EF3 | 73 km | 15.5 mi | 0 |
| May 8, 1988 | EF3 | 37 km | 32.0 mi | 0 |
| May 8, 1988 | EF3 | 78 km | 16.0 mi | 0 |
| Aug 15, 1978 | EF3 | 90 km | 6.4 mi | 0 |
| Jun 20, 1974 | EF3 | 52 km | 10.6 mi | 1 |
| Jun 14, 1974 | EF3 | 79 km | 48.6 mi | 0 |
| May 13, 1974 | EF3 | 56 km | 3.6 mi | 0 |
| Jul 12, 1971 | EF3 | 58 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 19°F (-7°C) | 1.2 in | Coldest |
| February | 24°F (-5°C) | 1.1 in | Driest |
| March | 36°F (2°C) | 2.3 in | |
| April | 48°F (9°C) | 3.3 in | |
| May | 60°F (16°C) | 3.8 in | |
| June | 69°F (21°C) | 4.5 in | Wettest |
| July | 73°F (23°C) | 3.8 in | Warmest |
| August | 71°F (22°C) | 4.3 in | |
| September | 63°F (17°C) | 4.1 in | |
| October | 51°F (11°C) | 2.6 in | |
| November | 37°F (3°C) | 2.3 in | |
| December | 24°F (-5°C) | 1.7 in |
Monmouth has a seasonal temperature swing of 54°F / from 19°F in January to 73°F in July. Total annual precipitation is 35.0 inches, with June being the wettest month (4.5") and February the driest (1.1").