Frost dates for Potosi 4 SW, MO
At Potosi 4 SW, the median last spring frost (32°F) is Apr 11 and the median first fall frost is Oct 28, for a typical growing season of 198 days. For a 90% chance that the last frost has passed, wait until Apr 30. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 11Last spring frost (median)50% chance of 32°F after this date
- Apr 30Safer planting date10% chance of 32°F after this date
- Oct 28First fall frost (median)50% chance of 32°F by this date
- 198 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 7 | Apr 24 | May 10 |
| 32°F | Mar 26 | Apr 11 | Apr 30 |
| 28°F | Mar 14 | Mar 31 | Apr 16 |
| 24°F | Mar 5 | Mar 21 | Apr 5 |
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 29 | Oct 16 | Oct 28 |
| 32°F | Oct 14 | Oct 28 | Nov 8 |
| 28°F | Oct 24 | Nov 4 | Nov 21 |
| 24°F | Nov 1 | Nov 15 | Dec 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 | 150 days | 173 days | 196 days |
| 32°F | 175 days | 198 days | 219 days |
| 28°F | 200 days | 220 days | 243 days |
| 24°F | 218 days | 241 days | 265 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 |
|---|---|---|---|
| 63664 | 6b | -5 to 0°F | 7 km |
| 63660 | 6b | -5 to 0°F | 12 km |
| 63622 | 6b | -5 to 0°F | 13 km |
| 63648 | 6b | -5 to 0°F | 15 km |
| 63631 | 6b | -5 to 0°F | 16 km |
| 63630 | 6b | -5 to 0°F | 18 km |
| 63674 | 6b | -5 to 0°F | 22 km |
| 63626 | 6b | -5 to 0°F | 23 km |
| 63623 | 6b | -5 to 0°F | 25 km |
| 63071 | 6b | -5 to 0°F | 28 km |
| 63030 | 6b | -5 to 0°F | 29 km |
| 63656 | 6b | -5 to 0°F | 34 km |
| 65439 | 6b | -5 to 0°F | 34 km |
| 63625 | 6b | -5 to 0°F | 39 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 USC00236826, at 37.8956, -90.8414, elevation 337 m (1,105 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 103.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Farmington (40 km)
- Steelville 2 N (48 km)
- Festus (54 km)
- Fredericktown (59 km)
- Union (63 km)
- Salem (68 km)
- Washington (73 km)
- Rosebud (77 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.