Frost dates for Fort Madison, IA
At Fort Madison, the median last spring frost (32°F) is Apr 12 and the median first fall frost is Oct 25, for a typical growing season of 194 days. For a 90% chance that the last frost has passed, wait until Apr 26. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 12Last spring frost (median)50% chance of 32°F after this date
- Apr 26Safer planting date10% chance of 32°F after this date
- Oct 25First fall frost (median)50% chance of 32°F by this date
- 194 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 10 | Apr 24 | May 7 |
| 32°F | Apr 1 | Apr 12 | Apr 26 |
| 28°F | Mar 18 | Apr 3 | Apr 17 |
| 24°F | Mar 7 | Mar 24 | Apr 7 |
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 | Oct 1 | Oct 16 | Oct 27 |
| 32°F | Oct 11 | Oct 25 | Nov 6 |
| 28°F | Oct 23 | Nov 4 | Nov 18 |
| 24°F | Nov 1 | Nov 12 | Nov 30 |
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 | 155 days | 173 days | 192 days |
| 32°F | 174 days | 194 days | 212 days |
| 28°F | 196 days | 215 days | 234 days |
| 24°F | 213 days | 234 days | 256 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 |
|---|---|---|---|
| 52627 | 6a | -10 to -5°F | 4 km |
| 62358 | 6a | -10 to -5°F | 7 km |
| 62354 | 6a | -10 to -5°F | 12 km |
| 52658 | 6a | -10 to -5°F | 12 km |
| 52624 | 6a | -10 to -5°F | 13 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 USC00133007, at 40.6222, -91.3339, elevation 162 m (530 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 110.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Donnellson (20 km)
- Burlington 2s (25 km)
- Burlington Muni Airport (25 km)
- Keokuk Lock Dam 19 (25 km)
- Mount Pleasant 1 SSW (41 km)
- Keosauqua (55 km)
- Fairfield (69 km)
- Columbus Junction (73 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.