Frost dates for Kirwin Dam, KS
At Kirwin Dam, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 7, for a typical growing season of 159 days. For a 90% chance that the last frost has passed, wait until May 12. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 12Safer planting date10% chance of 32°F after this date
- Oct 7First fall frost (median)50% chance of 32°F by this date
- 159 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 18 | Apr 30 | May 12 |
| 28°F | Apr 8 | Apr 20 | May 4 |
| 24°F | Mar 31 | Apr 11 | Apr 25 |
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 17 | Sep 30 | Oct 10 |
| 32°F | Sep 24 | Oct 7 | Oct 18 |
| 28°F | Sep 30 | Oct 15 | Oct 26 |
| 24°F | Oct 12 | 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 | 126 days | 143 days | 160 days |
| 32°F | 142 days | 159 days | 176 days |
| 28°F | 158 days | 176 days | 193 days |
| 24°F | 176 days | 196 days | 212 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 |
|---|---|---|---|
| 67644 | 6a | -10 to -5°F | 3 km |
| 67628 | 6a | -10 to -5°F | 11 km |
| 66951 | 6a | -10 to -5°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 USC00144357, at 39.6619, -99.1228, elevation 517 m (1,697 ft).
- Data quality: Estimated from nearby stations (2+ years), 13 years of freeze data.
- Average days per year at or below 32°F: 158.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Phillipsburg #2 (19 km)
- Alton 1 W (24 km)
- Smith Center (32 km)
- Webster Dam (38 km)
- Plainville 4wnw (51 km)
- Norton 9sse (62 km)
- Hill City Muni Airport (68 km)
- Hill City 1e (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.