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Weather & Climate in Grafton, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Grafton has a cool climate with an average annual temperature of 43°F (6°C). Winters average 13°F in January while summers reach 69°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 35.5 inches. The area receives 40.2 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,228 feet.
Temperature
13°F Jan (-11°C)
69°F Jul (21°C)
| Annual Average | 43.0°F |
| 20% below US avg | |
| January Average | 13°F (-11°C) |
| July Average | 69°F (21°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 1,228 ft (374 m) |
| Area | 0.3 sq mi (0.9 km²) |
| Population Density | 728/sq mi |
| Coordinates | 43.3307°N, 93.0687°W |
| Timezone | America/Chicago |
| County | Worth County County |
| Nearest Airport | Northeast Iowa Regional (CCY) 29 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 9.9 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 68.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Very Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| 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 | 121 km | 0 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
596 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 52 fatalities, 1,010 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 25, 2008 | EF5 | 88 km | 41.0 mi | 9 |
| May 15, 1968 | EF5 | 63 km | 62.1 mi | 13 |
| Oct 14, 1966 | EF5 | 76 km | 9.7 mi | 6 |
| Jun 17, 2010 | EF4 | 54 km | 16.9 mi | 1 |
| Jul 12, 1971 | EF4 | 51 km | 10.9 mi | 0 |
| Apr 30, 1967 | EF4 | 16 km | 7.6 mi | 0 |
| Apr 30, 1967 | EF4 | 40 km | 38.7 mi | 5 |
| Apr 30, 1967 | EF4 | 9 km | 13.3 mi | 0 |
| Apr 30, 1967 | EF4 | 64 km | 20.1 mi | 6 |
| May 5, 1965 | EF4 | 21 km | 41.6 mi | 0 |
| Sep 16, 1962 | EF4 | 87 km | 0.5 mi | 0 |
| Sep 1, 1961 | EF4 | 62 km | 26.6 mi | 0 |
| May 10, 1953 | EF4 | 47 km | 26.6 mi | 0 |
| May 10, 1953 | EF4 | 56 km | 162.0 mi | 2 |
| Jun 12, 2013 | EF3 | 71 km | 6.2 mi | 0 |
| Jun 17, 2010 | EF3 | 50 km | 18.2 mi | 0 |
| Jun 17, 2010 | EF3 | 49 km | 5.0 mi | 0 |
| Jun 17, 2010 | EF3 | 59 km | 4.3 mi | 0 |
| Jun 11, 2004 | EF3 | 43 km | 12.0 mi | 0 |
| Jul 19, 1994 | EF3 | 66 km | 23.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: SNAKE TRAIL (1,496 acres, 2024).
| Year | Name | Acres Burned | Distance |
| 2024 | SNAKE TRAIL | 1,496 | 92 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 13°F (-11°C) | 0.8 in | Coldest, Driest |
| February | 20°F (-7°C) | 0.8 in | |
| March | 33°F (0°C) | 1.9 in | |
| April | 46°F (8°C) | 3.2 in | |
| May | 59°F (15°C) | 3.9 in | |
| June | 69°F (21°C) | 4.5 in | Wettest |
| July | 69°F (21°C) | 4.3 in | |
| August | 70°F (21°C) | 4.3 in | Warmest |
| September | 61°F (16°C) | 4.0 in | |
| October | 49°F (10°C) | 2.5 in | |
| November | 33°F (1°C) | 1.6 in | |
| December | 19°F (-7°C) | 1.1 in |
Grafton has a seasonal temperature swing of 57°F / from 13°F in January to 70°F in August. Total annual precipitation is 33.0 inches, with June being the wettest month (4.5") and January the driest (0.8").