Washington Frost Dates & Growing Zones by City
So far we cover one Washington city with frost dates, Seattle. Its typical (50%) last spring frost is Mar 8, and its typical frost-free season is 259 days.
On the 2023 USDA hardiness map, these cities fall in zone 9a.
We take each city's dates from the nearest NOAA station that passes our quality rules (methodology).
| City | Last frost (50%) | First frost (50%) | Season (days, 50%) | Zone 2023 | Confidence | Planting calendar |
|---|---|---|---|---|---|---|
| Seattle frost dates | Mar 8 | Nov 23 | 259 | 9a | High | Seattle planting calendar |
Station match, data and rules: methodology. Long-term odds, not a forecast.