Frost dates for Sparta, WI
At Sparta, the median last spring frost (32°F) is May 9 and the median first fall frost is Oct 1, for a typical growing season of 144 days. For a 90% chance that the last frost has passed, wait until May 22. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 9Last spring frost (median)50% chance of 32°F after this date
- May 22Safer planting date10% chance of 32°F after this date
- Oct 1First fall frost (median)50% chance of 32°F by this date
- 144 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 | May 6 | May 19 | May 31 |
| 32°F | Apr 26 | May 9 | May 22 |
| 28°F | Apr 15 | Apr 29 | May 13 |
| 24°F | Apr 3 | Apr 18 | May 1 |
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 10 | Sep 23 | Oct 5 |
| 32°F | Sep 18 | Oct 1 | Oct 13 |
| 28°F | Sep 27 | Oct 11 | Oct 24 |
| 24°F | Oct 7 | Oct 22 | Nov 3 |
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 | 107 days | 125 days | 142 days |
| 32°F | 127 days | 144 days | 162 days |
| 28°F | 142 days | 163 days | 183 days |
| 24°F | 166 days | 186 days | 205 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 |
|---|---|---|---|
| 54656 | 4b | -25 to -20°F | 6 km |
| 54614 | 4b | -25 to -20°F | 11 km |
| 54644 | 4b | -25 to -20°F | 23 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 USC00477997, at 43.9364, -90.8164, elevation 238 m (782 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 165.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Cashton 3nnw (17 km)
- Cashton (22 km)
- La Crosse WFO (33 km)
- La Crosse Muni Airport (36 km)
- Viroqua (42 km)
- Mather 3 NW (46 km)
- Hillsboro 2sw (49 km)
- Hillsboro (50 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.