Frost dates for Sioux City Ang, IA
At Sioux City Ang, the median last spring frost (32°F) is Apr 29 and the median first fall frost is Oct 7, for a typical growing season of 161 days. For a 90% chance that the last frost has passed, wait until May 11. Nearby ZIP codes are in USDA hardiness zone 5a.
- Apr 29Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 7First fall frost (median)50% chance of 32°F by this date
- 161 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 25 | May 7 | May 21 |
| 32°F | Apr 15 | Apr 29 | May 11 |
| 28°F | Apr 5 | Apr 19 | May 2 |
| 24°F | Mar 25 | Apr 9 | Apr 23 |
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 18 | Sep 29 | Oct 11 |
| 32°F | Sep 24 | Oct 7 | Oct 21 |
| 28°F | Oct 2 | Oct 18 | Oct 30 |
| 24°F | Oct 14 | Oct 27 | Nov 9 |
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 | 125 days | 144 days | 160 days |
| 32°F | 143 days | 161 days | 178 days |
| 28°F | 160 days | 180 days | 198 days |
| 24°F | 181 days | 199 days | 217 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 |
|---|---|---|---|
| 51111 | 5a | -20 to -15°F | 3 km |
| 68776 | 5a | -20 to -15°F | 9 km |
| 51106 | 5a | -20 to -15°F | 9 km |
| 51101 | 5a | -20 to -15°F | 11 km |
| 51105 | 5a | -20 to -15°F | 12 km |
| 51103 | 5a | -20 to -15°F | 15 km |
| 51104 | 5a | -20 to -15°F | 16 km |
| 51007 | 5a | -20 to -15°F | 16 km |
| 57049 | 5a | -20 to -15°F | 18 km |
| 51108 | 5a | -20 to -15°F | 19 km |
| 51030 | 5a | -20 to -15°F | 19 km |
| 68743 | 5a | -20 to -15°F | 22 km |
| 51109 | 5a | -20 to -15°F | 25 km |
| 57038 | 5a | -20 to -15°F | 26 km |
| 51039 | 5a | -20 to -15°F | 28 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 USC00137702, at 42.3964, -96.3778, elevation 335 m (1,100 ft).
- Data quality: Representative (10+ years), 10 years of freeze data.
- Average days per year at or below 32°F: 160.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sioux City Gateway Airport (1 km)
- Onawa 3nw (42 km)
- Le Mars (47 km)
- Mapleton No.2 (55 km)
- Castana Exp. Farm (58 km)
- Battle Creek 3ne (66 km)
- Hawarden (68 km)
- Holstein (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.