Frost dates in Milwaukee, Wisconsin
NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.
Short answer
The average last spring frost in Milwaukee is April 19, and the average first fall frost is October 29, from NOAA's Milwaukee Mitchell Airport station, 8 miles from the middle of Milwaukee. 1 year in 10 the last frost comes after May 2, and the first one by October 15. That leaves about 193 frost-free days. Milwaukee is in USDA planting zone 6a.
Weather stations around Milwaukee
The first row is the date most people in Milwaukee go by. The others show how far the dates move across the area.
| Station | Last spring frost | First fall frost | Frost-free |
|---|---|---|---|
| Milwaukee Mitchell Airport 8 mi away, 670 ft | April 19 1 in 10 after May 2 | October 29 1 in 10 by October 15 | 193 days |
| Mt Mary College 3 mi away, 715 ft | April 26 1 in 10 after May 12 | October 18 1 in 10 by October 2 | 175 days |
| West Allis 4 mi away, 723 ft | April 26 1 in 10 after May 12 | October 22 1 in 10 by October 7 | 179 days |
| Hales Corners/Whitnall Park/Bo 9 mi away, 774 ft | May 3 1 in 10 after May 19 | October 14 1 in 10 by September 30 | 164 days |
| Brookfield Wwtp 11 mi away, 830 ft | April 30 1 in 10 after May 15 | October 14 1 in 10 by September 28 | 167 days |
Distances are from the middle of Milwaukee as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 53210, at the middle of the city.
Your exact ZIP code
Milwaukee covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
More frost dates
All of Wisconsin, station by station.
Other Wisconsin cities: Madison
Nearby: Rockford, IL · Chicago, IL · Aurora, IL
Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)
- US Census Bureau, 2025 city population estimates and place gazetteer