Frost dates for Little Sioux 2 NW, IA
At Little Sioux 2 NW, the median last spring frost (32°F) is May 1 and the median first fall frost is Oct 3, for a typical growing season of 155 days. For a 90% chance that the last frost has passed, wait until May 12. Nearby ZIP codes are in USDA hardiness zones 5a to 5b.
- May 1Last spring frost (median)50% chance of 32°F after this date
- May 12Safer planting date10% chance of 32°F after this date
- Oct 3First fall frost (median)50% chance of 32°F by this date
- 155 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 27 | May 8 | May 21 |
| 32°F | Apr 17 | May 1 | May 12 |
| 28°F | Apr 8 | Apr 22 | May 4 |
| 24°F | Mar 30 | Apr 12 | Apr 26 |
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 13 | Sep 26 | Oct 7 |
| 32°F | Sep 20 | Oct 3 | Oct 17 |
| 28°F | Sep 29 | Oct 14 | Oct 28 |
| 24°F | Oct 10 | Oct 25 | 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 | 120 days | 139 days | 156 days |
| 32°F | 137 days | 155 days | 174 days |
| 28°F | 155 days | 174 days | 194 days |
| 24°F | 175 days | 195 days | 214 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 |
|---|---|---|---|
| 51545 | 5a | -20 to -15°F | 4 km |
| 51523 | 5a | -20 to -15°F | 10 km |
| 51564 | 5b | -15 to -10°F | 11 km |
| 51557 | 5b | -15 to -10°F | 11 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 USC00134874, at 41.8264, -96.0506, elevation 312 m (1,025 ft).
- Data quality: Representative (10+ years), 18 years of freeze data.
- Average days per year at or below 32°F: 165.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Onawa 3nw (28 km)
- Logan (30 km)
- Castana Exp. Farm (32 km)
- Mapleton No.2 (43 km)
- Harlan (63 km)
- Denison (64 km)
- Sioux City Gateway Airport (68 km)
- Sioux City Ang (69 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.