Frost dates for Harrison 20 SSE, NE
At Harrison 20 SSE, the median last spring frost (32°F) is May 27 and the median first fall frost is Sep 11, for a typical growing season of 106 days. For a 90% chance that the last frost has passed, wait until Jun 14. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 27Last spring frost (median)50% chance of 32°F after this date
- Jun 14Safer planting date10% chance of 32°F after this date
- Sep 11First fall frost (median)50% chance of 32°F by this date
- 106 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 25 | Jun 10 | Jul 2 |
| 32°F | May 12 | May 27 | Jun 14 |
| 28°F | Apr 30 | May 14 | May 31 |
| 24°F | Apr 17 | May 2 | May 17 |
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 15 | Sep 1 | Sep 15 |
| 32°F | Aug 26 | Sep 11 | Sep 26 |
| 28°F | Sep 6 | Sep 23 | Oct 5 |
| 24°F | Sep 16 | Oct 2 | Oct 15 |
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 | 55 days | 80 days | 104 days |
| 32°F | 81 days | 106 days | 129 days |
| 28°F | 106 days | 129 days | 150 days |
| 24°F | 129 days | 150 days | 170 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 69346 | 5a | -20 to -15°F | 23 km |
| 69354 | 5a | -20 to -15°F | 30 km |
| 69339 | 5a | -20 to -15°F | 30 km |
| 69357 | 5a | -20 to -15°F | 35 km |
| 69361 | 5a | -20 to -15°F | 39 km |
| 82242 | 5a | -20 to -15°F | 41 km |
| 69358 | 5a | -20 to -15°F | 44 km |
| 82240 | 5a | -20 to -15°F | 44 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 USW00094077, at 42.4247, -103.7364, elevation 1343 m (4,406 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 208.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Agate 3 E (0 km)
- Plainsview Rch (25 km)
- Harrison (31 km)
- Fort Robinson (35 km)
- Harrison 4nw (39 km)
- Harrison 9ne (42 km)
- Mitchell 5e (53 km)
- Hemingford (56 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.