Frost dates for Sibley, IA
At Sibley, the median last spring frost (32°F) is May 5 and the median first fall frost is Oct 3, for a typical growing season of 152 days. For a 90% chance that the last frost has passed, wait until May 17. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 5Last spring frost (median)50% chance of 32°F after this date
- May 17Safer planting date10% chance of 32°F after this date
- Oct 3First fall frost (median)50% chance of 32°F by this date
- 152 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 | May 1 | May 12 | May 25 |
| 32°F | Apr 22 | May 5 | May 17 |
| 28°F | Apr 11 | Apr 25 | May 8 |
| 24°F | Apr 3 | Apr 15 | May 1 |
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 11 | Sep 27 | Oct 8 |
| 32°F | Sep 21 | Oct 3 | Oct 17 |
| 28°F | Sep 29 | Oct 13 | Oct 27 |
| 24°F | Oct 7 | Oct 24 | Nov 6 |
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 | 118 days | 136 days | 153 days |
| 32°F | 133 days | 152 days | 171 days |
| 28°F | 150 days | 171 days | 189 days |
| 24°F | 170 days | 189 days | 210 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 |
|---|---|---|---|
| 51249 | 4b | -25 to -20°F | 1 km |
| 51243 | 5a | -20 to -15°F | 13 km |
| 51232 | 5a | -20 to -15°F | 13 km |
| 56117 | 4b | -25 to -20°F | 14 km |
| 51354 | 5a | -20 to -15°F | 17 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 USC00137664, at 43.4047, -95.7483, elevation 466 m (1,529 ft).
- Data quality: Standard (24+ years of data), 26 years of freeze data.
- Average days per year at or below 32°F: 173.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sanborn (26 km)
- Sheldon (26 km)
- Rock Rapids (34 km)
- Lake Park (35 km)
- Primghar (37 km)
- Milford 4 NW (46 km)
- Spirit Lake (49 km)
- Sioux Center 2 SE (51 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.