Frost dates for Richfield 3 SSW, WI
At Richfield 3 SSW, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 16, for a typical growing season of 167 days. For a 90% chance that the last frost has passed, wait until May 16. Nearby ZIP codes are in USDA hardiness zones 5a to 5b.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 16Safer planting date10% chance of 32°F after this date
- Oct 16First fall frost (median)50% chance of 32°F by this date
- 167 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 28 | May 12 | May 28 |
| 32°F | Apr 16 | Apr 30 | May 16 |
| 28°F | Apr 5 | Apr 19 | May 4 |
| 24°F | Mar 23 | Apr 6 | Apr 21 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Sep 22 | Oct 4 | Oct 17 |
| 32°F | Oct 1 | Oct 16 | Oct 29 |
| 28°F | Oct 11 | Oct 27 | Nov 10 |
| 24°F | Oct 26 | Nov 6 | Nov 20 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 125 days | 145 days | 164 days |
| 32°F | 147 days | 167 days | 187 days |
| 28°F | 169 days | 190 days | 209 days |
| 24°F | 191 days | 213 days | 233 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 53017 | 5a | -20 to -15°F | 4 km |
| 53033 | 5a | -20 to -15°F | 5 km |
| 53046 | 5b | -15 to -10°F | 7 km |
| 53089 | 5b | -15 to -10°F | 8 km |
| 53029 | 5b | -15 to -10°F | 13 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00477148, at 43.2111, -88.2092, elevation 300 m (984 ft).
- Data quality: Estimated from nearby stations (2+ years), 10 years of freeze data.
- Average days per year at or below 32°F: 153.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Germantown (8 km)
- Jackson (12 km)
- Slinger Wastewater Plant (15 km)
- Brookfield Wastewater Plant (18 km)
- West Bend (20 km)
- Hartford Wastewater Plant (21 km)
- Mount Mary College (21 km)
- W Bend Public Works (22 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.