Frost dates for Sunnyside, WA
At Sunnyside, the median last spring frost (32°F) is May 1 and the median first fall frost is Oct 6, for a typical growing season of 157 days. For a 90% chance that the last frost has passed, wait until May 18. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- May 1Last spring frost (median)50% chance of 32°F after this date
- May 18Safer planting date10% chance of 32°F after this date
- Oct 6First fall frost (median)50% chance of 32°F by this date
- 157 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 1 | May 16 | Jun 7 |
| 32°F | Apr 16 | May 1 | May 18 |
| 28°F | Mar 28 | Apr 15 | May 1 |
| 24°F | Mar 5 | Mar 25 | 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 10 | Sep 25 | Oct 7 |
| 32°F | Sep 25 | Oct 6 | Oct 22 |
| 28°F | Oct 5 | Oct 19 | Nov 4 |
| 24°F | Oct 17 | Oct 31 | Nov 17 |
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 | 104 days | 127 days | 149 days |
| 32°F | 137 days | 157 days | 177 days |
| 28°F | 164 days | 187 days | 210 days |
| 24°F | 196 days | 221 days | 246 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 |
|---|---|---|---|
| 98930 | 7b | 5 to 10°F | 11 km |
| 98935 | 7a | 0 to 5°F | 22 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 USC00458207, at 46.3236, -120.0103, elevation 228 m (747 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 124.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sunnyside #2 (3 km)
- Moxee City 10 E (24 km)
- Prosser (24 km)
- Wapato (34 km)
- Priest Rapids Dam (37 km)
- Bickleton (43 km)
- Yakima Air Terminal (49 km)
- Yakima #2 (52 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.