Frost dates for Mount Pleasant 1 SSW, IA
At Mount Pleasant 1 SSW, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 10, for a typical growing season of 163 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 10First fall frost (median)50% chance of 32°F by this date
- 163 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 25 | May 9 | May 23 |
| 32°F | Apr 13 | Apr 30 | May 14 |
| 28°F | Apr 3 | Apr 17 | May 5 |
| 24°F | Mar 22 | Apr 5 | 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 | Oct 1 | Oct 13 |
| 32°F | Sep 24 | Oct 10 | Oct 23 |
| 28°F | Oct 3 | Oct 20 | Nov 2 |
| 24°F | Oct 16 | Oct 31 | Nov 13 |
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 | 144 days | 163 days |
| 32°F | 142 days | 163 days | 183 days |
| 28°F | 163 days | 185 days | 204 days |
| 24°F | 185 days | 206 days | 226 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 |
|---|---|---|---|
| 52641 | 5b | -15 to -10°F | 5 km |
| 52649 | 6a | -10 to -5°F | 13 km |
| 52645 | 5b | -15 to -10°F | 14 km |
| 52644 | 5b | -15 to -10°F | 16 km |
| 52652 | 5b | -15 to -10°F | 17 km |
| 52630 | 6a | -10 to -5°F | 19 km |
| 52647 | 5b | -15 to -10°F | 21 km |
| 52660 | 5b | -15 to -10°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 USC00135796, at 40.9486, -91.5647, elevation 222 m (730 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 130.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Donnellson (34 km)
- Fairfield (34 km)
- Washington (39 km)
- Columbus Junction (40 km)
- Fort Madison (41 km)
- Burlington Muni Airport (41 km)
- Keosauqua (41 km)
- Burlington 2s (42 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.