Frost dates for Des Moines Wsfo-Johnston, IA
At Des Moines Wsfo-Johnston, the median last spring frost (32°F) is Apr 19 and the median first fall frost is Oct 18, for a typical growing season of 179 days. For a 90% chance that the last frost has passed, wait until May 3. Nearby ZIP codes are in USDA hardiness zone 5b.
- Apr 19Last spring frost (median)50% chance of 32°F after this date
- May 3Safer planting date10% chance of 32°F after this date
- Oct 18First fall frost (median)50% chance of 32°F by this date
- 179 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 15 | Apr 30 | May 13 |
| 32°F | Apr 5 | Apr 19 | May 3 |
| 28°F | Mar 25 | Apr 9 | Apr 23 |
| 24°F | Mar 13 | Apr 1 | Apr 16 |
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 23 | Oct 7 | Oct 21 |
| 32°F | Oct 1 | Oct 18 | Oct 30 |
| 28°F | Oct 14 | Oct 27 | Nov 9 |
| 24°F | Oct 21 | Nov 4 | Nov 19 |
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 | 140 days | 159 days | 178 days |
| 32°F | 159 days | 179 days | 198 days |
| 28°F | 179 days | 199 days | 218 days |
| 24°F | 195 days | 217 days | 237 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 |
|---|---|---|---|
| 50131 | 5b | -15 to -10°F | 4 km |
| 50226 | 5b | -15 to -10°F | 7 km |
| 50109 | 5b | -15 to -10°F | 7 km |
| 50111 | 5b | -15 to -10°F | 8 km |
| 50322 | 5b | -15 to -10°F | 11 km |
| 50323 | 5b | -15 to -10°F | 14 km |
| 50243 | 5b | -15 to -10°F | 14 km |
| 50063 | 5b | -15 to -10°F | 19 km |
| 50263 | 5b | -15 to -10°F | 20 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 USC00132209, at 41.7367, -93.7236, elevation 292 m (959 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 135.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Ankeny (6 km)
- Des Moines Intl Airport (23 km)
- Ames 5 SE (27 km)
- Ames Muni Airport (30 km)
- Ames 8 WSW (32 km)
- Perry (34 km)
- Boone (37 km)
- Des Moines 17 E (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.