Frost dates for Spokane Intl Airport, WA
At Spokane Intl Airport, the median last spring frost (32°F) is Apr 26 and the median first fall frost is Oct 12, for a typical growing season of 168 days. For a 90% chance that the last frost has passed, wait until May 10. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 26Last spring frost (median)50% chance of 32°F after this date
- May 10Safer planting date10% chance of 32°F after this date
- Oct 12First fall frost (median)50% chance of 32°F by this date
- 168 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 26 | May 8 | May 26 |
| 32°F | Apr 9 | Apr 26 | May 10 |
| 28°F | Mar 15 | Apr 6 | Apr 28 |
| 24°F | Feb 26 | Mar 13 | Apr 4 |
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 | Oct 1 | Oct 14 |
| 32°F | Sep 29 | Oct 12 | Oct 28 |
| 28°F | Oct 7 | Oct 23 | Nov 10 |
| 24°F | Oct 16 | Nov 3 | Nov 25 |
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 | 122 days | 144 days | 163 days |
| 32°F | 147 days | 168 days | 192 days |
| 28°F | 174 days | 200 days | 227 days |
| 24°F | 203 days | 231 days | 260 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 |
|---|---|---|---|
| 99224 | 6b | -5 to 0°F | 3 km |
| 99001 | 6b | -5 to 0°F | 5 km |
| 99020 | 6b | -5 to 0°F | 7 km |
| 99204 | 7a | 0 to 5°F | 8 km |
| 99201 | 7a | 0 to 5°F | 8 km |
| 99014 | 6b | -5 to 0°F | 8 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 USW00024157, at 47.6217, -117.5281, elevation 717 m (2,353 ft).
- Data quality: Standard (24+ years of data), 26 years of freeze data.
- Average days per year at or below 32°F: 132.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Spokane WFO (10 km)
- Spokane Felts Field (17 km)
- Spokane 17 SSW (23 km)
- Deer Park Airport (40 km)
- Rosalia (45 km)
- Davenport (48 km)
- Harrington (56 km)
- St. John (59 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.