Frost dates for Sac City, IA
At Sac City, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 6, for a typical growing season of 158 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 30Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 6First fall frost (median)50% chance of 32°F by this date
- 158 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 28 | May 8 | May 21 |
| 32°F | Apr 15 | Apr 30 | 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 16 | Sep 28 | Oct 10 |
| 32°F | Sep 23 | Oct 6 | Oct 20 |
| 28°F | Oct 4 | Oct 17 | Oct 30 |
| 24°F | Oct 15 | Oct 28 | Nov 8 |
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 | 123 days | 142 days | 158 days |
| 32°F | 142 days | 158 days | 179 days |
| 28°F | 161 days | 180 days | 200 days |
| 24°F | 179 days | 200 days | 220 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 |
|---|---|---|---|
| 50583 | 5a | -20 to -15°F | 2 km |
| 50561 | 5a | -20 to -15°F | 10 km |
| 51450 | 5a | -20 to -15°F | 12 km |
| 50567 | 5a | -20 to -15°F | 14 km |
| 50535 | 5a | -20 to -15°F | 16 km |
| 51433 | 5a | -20 to -15°F | 19 km |
| 51466 | 5a | -20 to -15°F | 22 km |
| 51458 | 5a | -20 to -15°F | 24 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 USC00137312, at 42.4194, -94.9761, elevation 369 m (1,210 ft).
- Data quality: Standard (24+ years of data), 29 years of freeze data.
- Average days per year at or below 32°F: 159.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Rockwell City (29 km)
- Storm Lake (31 km)
- Carroll (41 km)
- Pocahontas (43 km)
- Ida Grove 5nw (44 km)
- Holstein (48 km)
- Battle Creek 3ne (49 km)
- Denison (52 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.