White Harbor Labs › Frost Dates › States › Oregon
Frost Dates in Oregon
First and last frost dates across Oregon, computed from 98 NOAA weather stations (1991–2020 climate normals). Your exact date depends on your city and microclimate — use the ZIP lookup on the main tool for a station-specific answer.
Last spring frost
Apr 25
statewide median · range Jan 31–Jun 11
First fall frost
Oct 20
statewide median · range Sep 6–Dec 27
Growing season
174 days
median · range 85–334
Stations used
98
NOAA 1991–2020 normals
Frost dates by city
Median dates from the nearest NOAA station to each city. The "cautious" date is the 10% spring value — planting after it means only a ~10% chance of a later frost.
| City | Nearest station | Last spring frost | First fall frost | Growing season | Safe transplant |
|---|---|---|---|---|---|
| Portland | Portland Intl Ap · 6 mi | Mar 13 (cautious: Apr 1) | Nov 19 | 247 days | Mar 27 |
| Eugene | Eugene-Mahlon Sweet Fld · 8 mi | Apr 11 (cautious: May 9) | Oct 23 | 196 days | Apr 25 |
| Salem | Salem Ap (Mcnary Field) · 3 mi | Apr 3 (cautious: Apr 27) | Nov 1 | 212 days | Apr 17 |
How frost varies across Oregon
Spring frost timing spans about 131 days across the state. Brookings in southwestern Oregon typically sees its last spring frost around January 31, while Burns Muni in eastern Oregon doesn't clear frost until about June 11. Within any city, low spots and valleys run colder than the station average; areas near buildings and pavement run warmer.
When to plant in Oregon
As a rule of thumb, cool-season crops (lettuce, peas, spinach) can go in 2–4 weeks before your last spring frost; warm-season transplants (tomatoes, peppers) should wait about 2 weeks after it — around May 9 for the statewide median. Check your city's row above rather than the statewide median: a 131-day statewide spread makes the city-level date the one that matters.
These are climate normals (what's typical), not forecasts. For the current year, watch the 10-day forecast around your planting date.
How this is computed
Statewide medians are the median of the 98 NOAA stations' median frost dates — half the stations run earlier, half later. City rows use the nearest station with 30-year freeze records. Dates are 32°F freeze probabilities from NOAA NCEI 1991–2020 U.S. Climate Normals; nothing is estimated or interpolated.
More states
Frequently asked questions
When is the last frost date in Oregon?
The statewide median last spring frost is April 25, but it ranges from January 31 to June 11 depending on where in the state you are. Use your city's row in the table above, or the ZIP lookup on the main tool, for a station-specific date.
When can I plant tomatoes outside in Oregon?
Warm-season transplants like tomatoes should wait about two weeks after your last spring frost — around May 9 for the statewide median. Your city may differ by weeks; check the "safe transplant" column in the city table.
How long is the growing season in Oregon?
The median growing season across 98 NOAA stations is 174 days, ranging from 85 to 334 days by location.
Why do frost dates vary so much within Oregon?
Frost timing follows latitude, elevation, and local terrain. Across Oregon, last spring frost dates span about 131 days — from around January 31 near Brookings to June 11 near Burns Muni. Microclimates (low spots, valleys, urban heat) shift dates further at the garden level.
Where does this data come from?
All frost dates are computed from the NOAA National Centers for Environmental Information 1991–2020 U.S. Climate Normals freeze data (public domain), using each station's 32°F freeze probability statistics. No dates are estimated or interpolated.