Frost dates for Pullman Moscow Regional Airport, WA
At Pullman Moscow Regional Airport, the median last spring frost (32°F) is Apr 29 and the median first fall frost is Oct 2, for a typical growing season of 159 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 29Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 2First 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 | May 2 | May 18 | Jun 14 |
| 32°F | Apr 7 | Apr 29 | May 14 |
| 28°F | Mar 9 | Apr 3 | Apr 27 |
| 24°F | Feb 15 | Mar 10 | 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 | Aug 28 | Sep 19 | Oct 5 |
| 32°F | Sep 17 | Oct 2 | Oct 25 |
| 28°F | Sep 29 | Oct 18 | Nov 15 |
| 24°F | Oct 9 | Nov 2 | Nov 29 |
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 | 89 days | 120 days | 147 days |
| 32°F | 133 days | 159 days | 187 days |
| 28°F | 165 days | 197 days | 232 days |
| 24°F | 204 days | 237 days | 270 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 |
|---|---|---|---|
| 99113 | 7a | 0 to 5°F | 19 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 USW00094129, at 46.7439, -117.1086, elevation 778 m (2,551 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 119.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Pullman 2 NW (6 km)
- Pomeroy (48 km)
- St. John (53 km)
- Rosalia (58 km)
- Lacrosse (60 km)
- Spokane 17 SSW (81 km)
- Dayton 1 WSW (83 km)
- Spokane Intl Airport (103 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.