All Countries
Weather & Climate in Grafton, WI
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Grafton experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 24°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 35.5 inches. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 763 feet.
Temperature
24°F Jan (-5°C)
72°F Jul (22°C)
| Annual Average | 47.8°F |
| 11% below US avg | |
| January Average | 24°F (-5°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 763 ft (233 m) |
| Area | 5.3 sq mi (13.8 km²) |
| Population Density | 2,303/sq mi |
| Coordinates | 43.3207°N, 87.9476°W |
| Timezone | America/Chicago |
| County | Ozaukee County County |
| Nearest Airport | General Mitchell International (MKE) 26 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 38.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 50.3 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 100.0 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Very Low |
| Drought | Very Low |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
| Coastal Flood | 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: M2.9.
| Mar 25, 2015 | 3 km WNW of Lake in the Hills, Illinois | M2.9 | 131 km | 6 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
351 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 12 fatalities, 469 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jul 18, 1996 | EF5 | 69 km | 13.3 mi | 0 |
| Apr 27, 1984 | EF4 | 51 km | 6.5 mi | 1 |
| Apr 4, 1981 | EF4 | 24 km | 1.8 mi | 3 |
| Apr 21, 1974 | EF4 | 86 km | 26.0 mi | 0 |
| Aug 22, 1964 | EF4 | 7 km | 2.2 mi | 0 |
| Jan 7, 2008 | EF3 | 91 km | 10.8 mi | 0 |
| Jun 23, 2004 | EF3 | 98 km | 33.3 mi | 0 |
| Jun 23, 2004 | EF3 | 90 km | 7.6 mi | 1 |
| Jun 5, 1980 | EF3 | 70 km | 10.7 mi | 0 |
| Apr 7, 1980 | EF3 | 85 km | 1.2 mi | 0 |
| Jun 5, 1977 | EF3 | 84 km | 69.5 mi | 0 |
| Apr 21, 1974 | EF3 | 70 km | 22.2 mi | 0 |
| Apr 21, 1974 | EF3 | 68 km | 58.6 mi | 2 |
| Jul 19, 1963 | EF3 | 86 km | 10.6 mi | 0 |
| Aug 28, 2018 | EF2 | 57 km | 3.9 mi | 0 |
| Jul 22, 2010 | EF2 | 55 km | 1.0 mi | 0 |
| Jun 21, 2010 | EF2 | 68 km | 5.2 mi | 0 |
| Jun 1, 2000 | EF2 | 56 km | 17.0 mi | 0 |
| Jul 18, 1996 | EF2 | 75 km | 6.4 mi | 1 |
| Apr 19, 1996 | EF2 | 97 km | 2.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
7 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (1,524 acres, 2006).
| Year | Name | Acres Burned | Distance |
| 2006 | UNNAMED | 1,524 | 59 km |
| 2010 | RX BURN | 1,236 | 58 km |
| 1994 | SOMMERS | 938 | 65 km |
| 1988 | PEACHY RD | 812 | 63 km |
| 2006 | UNNAMED | 612 | 67 km |
| 2007 | TOWER RD 2 | 592 | 63 km |
| 2024 | RX-HWY Y - SOUTH | 553 | 76 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-5°C) | 1.4 in | Coldest |
| February | 24°F (-4°C) | 1.1 in | Driest |
| March | 34°F (1°C) | 2.0 in | |
| April | 45°F (7°C) | 3.1 in | |
| May | 55°F (13°C) | 2.8 in | |
| June | 65°F (18°C) | 3.3 in | |
| July | 72°F (22°C) | 3.4 in | Warmest |
| August | 69°F (21°C) | 3.7 in | Wettest |
| September | 62°F (16°C) | 3.7 in | |
| October | 50°F (10°C) | 2.4 in | |
| November | 38°F (3°C) | 2.3 in | |
| December | 25°F (-4°C) | 1.9 in |
Grafton has a seasonal temperature swing of 48°F / from 24°F in January to 72°F in July. Total annual precipitation is 31.1 inches, with August being the wettest month (3.7") and February the driest (1.1").