Frost dates for Whitewater, WI
At Whitewater, the median last spring frost (32°F) is May 2 and the median first fall frost is Oct 9, for a typical growing season of 157 days. For a 90% chance that the last frost has passed, wait until May 20. Nearby ZIP codes are in USDA hardiness zone 5b.
- May 2Last spring frost (median)50% chance of 32°F after this date
- May 20Safer planting date10% chance of 32°F after this date
- Oct 9First fall frost (median)50% chance of 32°F by this date
- 157 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 30 | May 16 | Jun 1 |
| 32°F | Apr 18 | May 2 | May 20 |
| 28°F | Apr 6 | Apr 20 | May 6 |
| 24°F | Mar 25 | Apr 8 | Apr 23 |
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 16 | Sep 30 | Oct 12 |
| 32°F | Sep 25 | Oct 9 | Oct 24 |
| 28°F | Oct 5 | Oct 22 | Nov 4 |
| 24°F | Oct 20 | Nov 2 | Nov 18 |
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 | 116 days | 134 days | 154 days |
| 32°F | 136 days | 157 days | 179 days |
| 28°F | 159 days | 182 days | 205 days |
| 24°F | 184 days | 207 days | 228 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 |
|---|---|---|---|
| 53190 | 5b | -15 to -10°F | 5 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 USC00479190, at 42.8508, -88.7247, elevation 267 m (875 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 152.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Fort Atkinson (12 km)
- Jefferson Wastewater Plant (17 km)
- Sullivan 3se (19 km)
- Delavan Wastewater Plant (24 km)
- Lake Mills Wastewater Plant (29 km)
- Oconomowoc Wastewater Plant (33 km)
- Clinton Wastewater Plant (36 km)
- Watertown Wastewater Plant (36 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.