Oregon Frost Dates & Growing Zones by City
Portland is our only Oregon city with frost dates so far: typical (50%) last spring frost Feb 25, typical frost-free season 280 days.
By the 2023 USDA hardiness map, these cities are in zones 8b and 9a.
Dates come from the nearest NOAA station to each city that meets our quality rules, as the methodology explains.
| City | Last frost (50%) | First frost (50%) | Season (days, 50%) | Zone 2023 | Confidence | Planting calendar |
|---|---|---|---|---|---|---|
| Portland frost dates | Feb 25 | Dec 1 | 280 | 8b–9a | High | Portland planting calendar |
Station match, data and rules: methodology. Long-term odds, not a forecast.