Frost dates for Keosauqua, IA
At Keosauqua, the median last spring frost (32°F) is Apr 26 and the median first fall frost is Oct 13, for a typical growing season of 169 days. For a 90% chance that the last frost has passed, wait until May 11. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- Apr 26Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 13First fall frost (median)50% chance of 32°F by this date
- 169 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 23 | May 6 | May 20 |
| 32°F | Apr 10 | Apr 26 | May 11 |
| 28°F | Mar 31 | Apr 14 | Apr 30 |
| 24°F | Mar 16 | Apr 3 | Apr 20 |
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 19 | Oct 3 | Oct 16 |
| 32°F | Sep 28 | Oct 13 | Oct 26 |
| 28°F | Oct 7 | Oct 23 | Nov 4 |
| 24°F | Oct 20 | Nov 1 | Nov 14 |
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 | 129 days | 150 days | 170 days |
| 32°F | 147 days | 169 days | 189 days |
| 28°F | 169 days | 190 days | 210 days |
| 24°F | 189 days | 210 days | 233 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 |
|---|---|---|---|
| 52565 | 5b | -15 to -10°F | 3 km |
| 52573 | 6a | -10 to -5°F | 12 km |
| 52535 | 5b | -15 to -10°F | 14 km |
| 52551 | 5b | -15 to -10°F | 14 km |
| 52542 | 6a | -10 to -5°F | 15 km |
| 52620 | 6a | -10 to -5°F | 15 km |
| 52570 | 5b | -15 to -10°F | 16 km |
| 52651 | 6a | -10 to -5°F | 19 km |
| 52588 | 5b | -15 to -10°F | 21 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 USC00134389, at 40.7356, -91.9697, elevation 192 m (629 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 128.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Fairfield (32 km)
- Donnellson (36 km)
- Bloomfield (37 km)
- Mount Pleasant 1 SSW (41 km)
- Fort Madison (55 km)
- Ottumwa Industrial Airport (58 km)
- Keokuk Lock Dam 19 (63 km)
- Washington (65 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.