Frost dates for Omak Airport, WA
At Omak Airport, 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 160 days. For a 90% chance that the last frost has passed, wait until May 15. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 15Safer planting date10% chance of 32°F after this date
- Oct 7First fall frost (median)50% chance of 32°F by this date
- 160 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 13 | Jun 1 |
| 32°F | Apr 14 | Apr 30 | May 15 |
| 28°F | Mar 26 | Apr 14 | May 2 |
| 24°F | Mar 4 | Mar 24 | Apr 14 |
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 12 | Sep 28 | Oct 11 |
| 32°F | Sep 23 | Oct 7 | Oct 22 |
| 28°F | Oct 3 | Oct 19 | Nov 4 |
| 24°F | Oct 13 | Oct 30 | Nov 18 |
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 | 113 days | 136 days | 156 days |
| 32°F | 139 days | 160 days | 183 days |
| 28°F | 163 days | 188 days | 215 days |
| 24°F | 194 days | 222 days | 250 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 |
|---|---|---|---|
| 98849 | 6b | -5 to 0°F | 12 km |
| 98840 | 7a | 0 to 5°F | 19 km |
| 98841 | 6b | -5 to 0°F | 19 km |
| 98819 | 6b | -5 to 0°F | 27 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 USW00094197, at 48.4608, -119.5167, elevation 395 m (1,296 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 145.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Tonasket 4 NNE (36 km)
- Tonasket 11ne (42 km)
- Winthrop 1 WSW (50 km)
- Chief Joseph Dam (53 km)
- Methow 2 S (54 km)
- Republic (61 km)
- Coulee Dam 1 SW (68 km)
- Mazama (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.