Frost dates for St. Peter, MN
At St. Peter, the median last spring frost (32°F) is May 2 and the median first fall frost is Oct 4, for a typical growing season of 153 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 2Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 153 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 10 | May 23 |
| 32°F | Apr 19 | May 2 | May 14 |
| 28°F | Apr 8 | Apr 22 | May 5 |
| 24°F | Mar 31 | Apr 12 | Apr 26 |
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 13 | Sep 27 | Oct 8 |
| 32°F | Sep 21 | Oct 4 | Oct 16 |
| 28°F | Sep 28 | Oct 13 | Oct 26 |
| 24°F | Oct 10 | Oct 25 | Nov 7 |
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 | 119 days | 137 days | 154 days |
| 32°F | 136 days | 153 days | 170 days |
| 28°F | 155 days | 173 days | 193 days |
| 24°F | 175 days | 194 days | 213 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 |
|---|---|---|---|
| 56082 | 4b | -25 to -20°F | 7 km |
| 56050 | 5a | -20 to -15°F | 7 km |
| 56017 | 5a | -20 to -15°F | 12 km |
| 56058 | 4b | -25 to -20°F | 14 km |
| 56063 | 5a | -20 to -15°F | 17 km |
| 56057 | 4b | -25 to -20°F | 21 km |
| 56028 | 5a | -20 to -15°F | 22 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 USC00217405, at 44.3222, -93.9656, elevation 242 m (795 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 163.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mankato (19 km)
- Gaylord (33 km)
- New Ulm 3se (35 km)
- New Ulm 2 SE (42 km)
- Waseca S Rsch & Outreach Center (45 km)
- Jordan 1ssw (45 km)
- Amboy (51 km)
- Brownton Wastewater Plant (55 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.