Frost dates in Portland, Oregon
NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.
Short answer
The average last spring frost in Portland is March 13, and the average first fall frost is November 19, from NOAA's Portland Intl Airport station, 4 miles from the middle of Portland. 1 year in 10 the last frost comes after April 1, and the first one by October 29. That leaves about 251 frost-free days. Portland is in USDA planting zone 8b.
Weather stations around Portland
The first row is the date most people in Portland go by. The others show how far the dates move across the area.
| Station | Last spring frost | First fall frost | Frost-free |
|---|---|---|---|
| Portland Intl Airport 4 mi away, 19 ft | March 13 1 in 10 after April 1 | November 19 1 in 10 by October 29 | 251 days |
| Portland Kgw-Tv 2 mi away, 159 ft | February 25 1 in 10 after March 21 | December 1 1 in 10 by November 10 | 279 days |
| Portland Wfo 6 mi away, 21 ft | March 13 1 in 10 after April 5 | November 22 1 in 10 by November 3 | 254 days |
| Vancouver Pearson Airport 6 mi away, 30 ft | March 29 1 in 10 after April 18 | November 9 1 in 10 by October 22 | 225 days |
| Nature Park-Beaverton 10 mi away, 185 ft | February 11 1 in 10 after March 5 | December 5 1 in 10 by November 11 | 297 days |
Distances are from the middle of Portland as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 97212, at the middle of the city.
Your exact ZIP code
Portland covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
More frost dates
All of Oregon, station by station.
Other Oregon cities: Salem · Eugene
Nearby: Vancouver, WA · Tacoma, WA
Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)
- US Census Bureau, 2025 city population estimates and place gazetteer