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Weather & Climate in Mason City, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Mason City experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 16°F in January while summers reach 72°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 36.3 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,106 feet.
Temperature
16°F Jan (-9°C)
72°F Jul (22°C)
| Annual Average | 45.6°F |
| 16% below US avg | |
| January Average | 16°F (-9°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 1,106 ft (337 m) |
| Area | 28.1 sq mi (72.8 km²) |
| Population Density | 962/sq mi |
| Coordinates | 43.1486°N, 93.1998°W |
| Timezone | America/Chicago |
| County | Cerro Gordo County County |
| Nearest Airport | Northeast Iowa Regional (CCY) 30 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 69.6 / 100 |
| Social Vulnerability | 46.3 / 100 |
| Community Resilience | 92.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| 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 High |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1 earthquake (M2.5+) recorded within 150 km since 1990. Strongest on record: M2.8.
| Apr 25, 2017 | Near Mankato, Minnesota | M2.8 | 132 km | 0 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
623 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 53 fatalities, 1,035 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 25, 2008 | EF5 | 72 km | 41.0 mi | 9 |
| May 15, 1968 | EF5 | 43 km | 62.1 mi | 13 |
| Oct 14, 1966 | EF5 | 53 km | 9.7 mi | 6 |
| Jun 17, 2010 | EF4 | 59 km | 16.9 mi | 1 |
| May 30, 1989 | EF4 | 97 km | 11.0 mi | 0 |
| Jul 12, 1971 | EF4 | 62 km | 10.9 mi | 0 |
| Apr 30, 1967 | EF4 | 17 km | 13.3 mi | 0 |
| Apr 30, 1967 | EF4 | 50 km | 38.7 mi | 5 |
| Apr 30, 1967 | EF4 | 77 km | 20.1 mi | 6 |
| Apr 30, 1967 | EF4 | 34 km | 7.6 mi | 0 |
| May 5, 1965 | EF4 | 34 km | 41.6 mi | 0 |
| Aug 29, 1964 | EF4 | 88 km | 15.8 mi | 0 |
| Sep 1, 1961 | EF4 | 44 km | 26.6 mi | 0 |
| May 10, 1953 | EF4 | 27 km | 26.6 mi | 0 |
| May 10, 1953 | EF4 | 73 km | 162.0 mi | 2 |
| Jun 12, 2013 | EF3 | 49 km | 6.2 mi | 0 |
| Jun 17, 2010 | EF3 | 79 km | 4.3 mi | 0 |
| Jun 17, 2010 | EF3 | 68 km | 5.0 mi | 0 |
| Jun 17, 2010 | EF3 | 64 km | 18.2 mi | 0 |
| Jun 11, 2004 | EF3 | 60 km | 12.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 16°F (-9°C) | 0.8 in | Coldest, Driest |
| February | 21°F (-6°C) | 0.8 in | |
| March | 33°F (0°C) | 1.9 in | |
| April | 47°F (8°C) | 3.2 in | |
| May | 59°F (15°C) | 4.0 in | |
| June | 69°F (21°C) | 4.7 in | Wettest |
| July | 72°F (22°C) | 4.5 in | Warmest |
| August | 70°F (21°C) | 4.2 in | |
| September | 62°F (17°C) | 3.9 in | |
| October | 50°F (10°C) | 2.5 in | |
| November | 33°F (1°C) | 1.7 in | |
| December | 20°F (-7°C) | 1.1 in |
Mason City has a seasonal temperature swing of 56°F / from 16°F in January to 72°F in July. Total annual precipitation is 33.2 inches, with June being the wettest month (4.7") and January the driest (0.8").