Frost dates for Harrisburg 12wnw, NE
At Harrisburg 12wnw, the median last spring frost (32°F) is May 24 and the median first fall frost is Sep 20, for a typical growing season of 117 days. For a 90% chance that the last frost has passed, wait until Jun 12. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 24Last spring frost (median)50% chance of 32°F after this date
- Jun 12Safer planting date10% chance of 32°F after this date
- Sep 20First fall frost (median)50% chance of 32°F by this date
- 117 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 22 | Jun 6 | Jun 23 |
| 32°F | May 11 | May 24 | Jun 12 |
| 28°F | Apr 29 | May 12 | May 28 |
| 24°F | Apr 17 | May 2 | May 15 |
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 | Aug 28 | Sep 12 | Sep 24 |
| 32°F | Sep 6 | Sep 20 | Oct 3 |
| 28°F | Sep 13 | Sep 29 | Oct 12 |
| 24°F | Sep 23 | Oct 8 | Oct 22 |
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 | 75 days | 97 days | 117 days |
| 32°F | 95 days | 117 days | 136 days |
| 28°F | 118 days | 137 days | 156 days |
| 24°F | 136 days | 157 days | 178 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 |
|---|---|---|---|
| 69352 | 5a | -20 to -15°F | 19 km |
| 69345 | 5a | -20 to -15°F | 21 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 USC00253605, at 41.6331, -103.9542, elevation 1387 m (4,550 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 188.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Scottsbluff 1e (37 km)
- Scottsbluff Heilig Airport (40 km)
- Mitchell 5e (41 km)
- Bridgeport 18wsw (49 km)
- Minatare Dam (usbr) (50 km)
- Kimball 2ne (51 km)
- Bushnell 15s (70 km)
- Bridgeport (71 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.