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Weather & Climate in Marengo, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Marengo 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 275 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 36.0 inches. The area receives 27.9 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 736 feet.
Temperature
19°F Jan (-7°C)
73°F Jul (23°C)
| Annual Average | 48.2°F |
| 11% below US avg | |
| January Average | 19°F (-7°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 736 ft (224 m) |
| Area | 2.1 sq mi (5.5 km²) |
| Population Density | 1,332/sq mi |
| Coordinates | 41.7962°N, 92.0681°W |
| Timezone | America/Chicago |
| County | Iowa County County |
| Nearest Airport | The Eastern Iowa (CID) 20 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 28.2 / 100 |
| Social Vulnerability | 19.4 / 100 |
| Community Resilience | 94.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tornado History
652 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 23 fatalities, 581 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 15, 1968 | EF5 | 98 km | 13.1 mi | 5 |
| Mar 31, 2023 | EF4 | 54 km | 19.9 mi | 0 |
| Mar 13, 1990 | EF4 | 72 km | 19.0 mi | 0 |
| Aug 12, 1974 | EF4 | 11 km | 2.0 mi | 0 |
| Aug 12, 1974 | EF4 | 78 km | 5.0 mi | 0 |
| Aug 26, 1965 | EF4 | 57 km | 4.7 mi | 1 |
| Apr 11, 1965 | EF4 | 95 km | 91.5 mi | 1 |
| Apr 30, 1954 | EF4 | 43 km | 80.4 mi | 0 |
| Mar 31, 2023 | EF3 | 85 km | 26.1 mi | 0 |
| Jul 19, 2018 | EF3 | 81 km | 9.2 mi | 0 |
| Jul 19, 2018 | EF3 | 86 km | 8.4 mi | 0 |
| May 25, 2008 | EF3 | 90 km | 32.0 mi | 0 |
| Jun 1, 2007 | EF3 | 94 km | 15.8 mi | 0 |
| May 21, 2004 | EF3 | 35 km | 3.0 mi | 0 |
| May 11, 2000 | EF3 | 86 km | 18.6 mi | 1 |
| May 15, 1998 | EF3 | 64 km | 47.0 mi | 0 |
| Jul 27, 1995 | EF3 | 95 km | 20.0 mi | 0 |
| Jun 19, 1993 | EF3 | 82 km | 9.0 mi | 0 |
| Jul 13, 1992 | EF3 | 89 km | 5.0 mi | 0 |
| Sep 16, 1978 | EF3 | 94 km | 31.8 mi | 6 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
4 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (939 acres, 2009).
| Year | Name | Acres Burned | Distance |
| 2009 | UNNAMED | 939 | 18 km |
| 2010 | FOLEY | 786 | 14 km |
| 2011 | ACE AUTO | 676 | 5 km |
| 2011 | IRCP WUI ROFAE #2 FY11 | 510 | 24 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 19°F (-7°C) | 1.0 in | Coldest |
| February | 25°F (-4°C) | 0.9 in | Driest |
| March | 37°F (3°C) | 2.2 in | |
| April | 50°F (10°C) | 3.6 in | |
| May | 61°F (16°C) | 4.1 in | |
| June | 71°F (21°C) | 4.6 in | Wettest |
| July | 73°F (23°C) | 4.3 in | Warmest |
| August | 72°F (22°C) | 4.5 in | |
| September | 64°F (18°C) | 4.0 in | |
| October | 52°F (11°C) | 2.7 in | |
| November | 37°F (3°C) | 2.3 in | |
| December | 24°F (-4°C) | 1.4 in |
Marengo has a seasonal temperature swing of 54°F / from 19°F in January to 73°F in July. Total annual precipitation is 35.7 inches, with June being the wettest month (4.6") and February the driest (0.9").