When Is the Last Frost in Oregon?
The average last spring frost in Oregon falls between March 12 and June 4 for most ZIP codes, with a statewide median of April 14. At the average date a later frost is still a coin flip, so tender plants wait for the safer 90% date.
| City | Last frost | 90% safe after | First frost | Growing season |
|---|---|---|---|---|
| Portland | Feb 25 | Mar 21 | Dec 1 | 280 days |
| Salem | Apr 3 | Apr 27 | Nov 1 | 212 days |
| Eugene | Apr 11 | May 9 | Oct 23 | 196 days |
| Gresham | Mar 16 | Apr 12 | Nov 20 | 250 days |
| Hillsboro | Apr 16 | May 3 | Oct 23 | 191 days |
| Bend | Jun 6 | Jun 22 | Sep 20 | 105 days |
| Beaverton | Feb 11 | Mar 5 | Dec 5 | 303 days |
| Medford | Apr 8 | Apr 30 | Oct 29 | 204 days |
| Corvallis | Apr 17 | May 8 | Oct 28 | 194 days |
| Springfield | Apr 11 | May 9 | Oct 23 | 196 days |
| Grants Pass | Apr 8 | May 1 | Oct 28 | 201 days |
| McMinnville | Apr 5 | Apr 27 | Nov 7 | 216 days |
| Woodburn | Mar 16 | Apr 7 | Nov 14 | 242 days |
| Roseburg | Mar 31 | Apr 26 | Nov 5 | 215 days |
| Klamath Falls | Jun 9 | Jun 26 | Sep 18 | 99 days |
| Lebanon | Mar 14 | Apr 14 | Nov 18 | 248 days |
| Hermiston | Apr 27 | May 11 | Oct 7 | 163 days |
| Pendleton | Apr 22 | May 8 | Oct 9 | 170 days |
| Burns | Jun 11 | Jun 28 | Sep 6 | 85 days |
Last and first frost: 50% (median) dates of the last spring and first fall 32 °F night. 90% safe after: only a 10% chance of a later spring frost. First frost dates in January fall in the following winter. Each city uses the NOAA station nearest the ZIP code closest to its center.
Across all 172 Oregon weather stations with frost records, median last frost dates run from January 31 at Brookings 2 SE, OR to June 11 at O O Rch, OR. Elevation, valleys that collect cold air and distance from large water bodies explain most of the spread, so a garden a few miles from a listed city can differ by a week or more. The ZIP code lookup above uses the same NOAA data as the frost date calculator for every US ZIP code.
When Is the First Frost in Oregon?
The average first fall frost in Oregon arrives between September 18 and November 30 for most ZIP codes, with a median of October 28. Tomatoes, peppers, basil and squash are damaged at 32 °F, so harvest or cover them before then.
Fall frost can come early: Portland has a 10% chance of frost before November 10, Salem has a 10% chance of frost before October 16 and Eugene has a 10% chance of frost before October 6. Hardy crops such as kale, spinach and cabbage tolerate light frosts and keep producing after the first frost date.
When to Plant Tomatoes in Oregon?
Transplant tomatoes in Oregon 1 to 2 weeks after the local average last frost, once nights stay above about 50 °F: Mar 4 – Mar 11 in Portland, Apr 10 – Apr 17 in Salem and Apr 18 – Apr 25 in Eugene. Start seeds indoors 6 to 8 weeks before the last frost.
| City | Start seeds indoors | Transplant outdoors | Lowest-risk transplant |
|---|---|---|---|
| Portland | Dec 31 – Jan 14 | Mar 4 – Mar 11 | after Mar 21 |
| Salem | Feb 6 – Feb 20 | Apr 10 – Apr 17 | after Apr 27 |
| Eugene | Feb 14 – Feb 28 | Apr 18 – Apr 25 | after May 9 |
| Gresham | Jan 19 – Feb 2 | Mar 23 – Mar 30 | after Apr 12 |
| Hillsboro | Feb 19 – Mar 5 | Apr 23 – Apr 30 | after May 3 |
| Bend | Apr 11 – Apr 25 | Jun 13 – Jun 20 | after Jun 22 |
| Beaverton | Dec 17 – Dec 31 | Feb 18 – Feb 25 | after Mar 5 |
| Medford | Feb 11 – Feb 25 | Apr 15 – Apr 22 | after Apr 30 |
| Corvallis | Feb 20 – Mar 6 | Apr 24 – May 1 | after May 8 |
| Springfield | Feb 14 – Feb 28 | Apr 18 – Apr 25 | after May 9 |
| Grants Pass | Feb 11 – Feb 25 | Apr 15 – Apr 22 | after May 1 |
| McMinnville | Feb 8 – Feb 22 | Apr 12 – Apr 19 | after Apr 27 |
| Woodburn | Jan 19 – Feb 2 | Mar 23 – Mar 30 | after Apr 7 |
| Roseburg | Feb 3 – Feb 17 | Apr 7 – Apr 14 | after Apr 26 |
| Klamath Falls | Apr 14 – Apr 28 | Jun 16 – Jun 23 | after Jun 26 |
| Lebanon | Jan 17 – Jan 31 | Mar 21 – Mar 28 | after Apr 14 |
| Hermiston | Mar 2 – Mar 16 | May 4 – May 11 | after May 11 |
| Pendleton | Feb 25 – Mar 11 | Apr 29 – May 6 | after May 8 |
| Burns | Apr 16 – Apr 30 | Jun 18 – Jun 25 | after Jun 28 |
Indoors: 6–8 weeks before the average last frost. Outdoors: 1–2 weeks after it. Lowest-risk: after the date with only a 10% chance of a later frost. Rules of thumb; check the 10-day forecast and wait for soil near 60 °F.
Tomatoes stall below about 50 °F at night and are killed by frost, so a week or two of waiting after the average date costs little. The tomato plant care guide covers light, watering and feeding once plants are in the ground.
What Can You Plant in Portland and When?
Portland's average last frost of February 25 anchors its spring planting calendar: peas and spinach go in from January 14, broccoli and lettuce transplants from January 28, and tomatoes, peppers and squash after March 4.
| Crop | Start seeds indoors | Plant outdoors | Frost tolerance |
|---|---|---|---|
| Peas | — | Jan 14 – Jan 28direct sow, 4–6 weeks before last frost | hardy |
| Spinach | — | Jan 14 – Feb 4direct sow, 3–6 weeks before last frost | hardy |
| Radishes | — | Jan 21 – Feb 4direct sow, 3–5 weeks before last frost | hardy |
| Onions (sets) | — | Jan 28 – Feb 11plant, 2–4 weeks before last frost | hardy |
| Potatoes | — | Jan 28 – Feb 11plant, 2–4 weeks before last frost | half-hardy |
| Broccoli & cabbage | Dec 31 – Jan 14 | Jan 28 – Feb 11transplant, 2–4 weeks before last frost | hardy |
| Lettuce | Jan 14 – Jan 28 | Jan 28 – Feb 11transplant, 2–4 weeks before last frost | hardy |
| Beets | — | Jan 28 – Feb 11direct sow, 2–4 weeks before last frost | half-hardy |
| Carrots | — | Feb 4 – Feb 11direct sow, 2–3 weeks before last frost | half-hardy |
| Tomatoes | Dec 31 – Jan 14 | Mar 4 – Mar 11transplant, 1–2 weeks after last frost | tender |
| Basil | Dec 31 – Jan 14 | Mar 4 – Mar 18transplant, 1–3 weeks after last frost | tender |
| Peppers | Dec 17 – Dec 31 | Mar 11 – Mar 18transplant, 2–3 weeks after last frost | tender |
| Eggplant | Dec 17 – Dec 31 | Mar 11 – Mar 18transplant, 2–3 weeks after last frost | tender |
| Green beans | — | Mar 4 – Mar 18direct sow, 1–3 weeks after last frost | tender |
| Sweet corn | — | Mar 4 – Mar 18direct sow, 1–3 weeks after last frost | tender |
| Cucumbers | Jan 28 – Feb 4 | Mar 4 – Mar 18transplant, 1–3 weeks after last frost | tender |
| Squash & zucchini | Jan 28 – Feb 4 | Mar 4 – Mar 18transplant, 1–3 weeks after last frost | tender |
| Watermelon | Jan 28 – Feb 4 | Mar 11 – Mar 18transplant, 2–3 weeks after last frost | tender |
Dates for Portland (last frost Feb 25, NOAA station Portland Kgw-Tv, OR, 3 miles from ZIP 97212). General rules of thumb; wait for soil near 50 °F for most seeds and 60 °F for beans, corn and squash.
How Long Is the Growing Season in Oregon?
The frost-free growing season in Oregon lasts about 105 to 270 days for most ZIP codes, with a median of 196 days. Among the listed cities, Burns has the shortest season at 85 days and Beaverton the longest at 303.
Season length decides which varieties ripen: compare it with the “days to maturity” on seed packets, counted from transplanting for tomatoes and peppers. NOAA stations in Oregon range from 84 days at Enterprise 20 NNE, OR to 349 days at Brookings, OR. Planning beds before the season starts helps in short seasons — a plant spacing calculator for vegetable beds shows how many transplants fit.
What Hardiness Zones Are in Oregon?
Oregon spans USDA hardiness zones 5b to 9b, with zone 8b the most common. Zones describe winter cold and decide which perennials survive, while frost dates set when to plant annual vegetables and flowers.
The Oregon planting zone map with the zone of each city shows how the zones are spread across the state and which plants are hardy in all of them.
Frequently Asked Questions
- When is the last frost in Oregon?
- The average last spring frost in Oregon falls between March 12 and June 4 for most ZIP codes, with a statewide median of April 14. Among major cities it ranges from February 11 in Beaverton to June 11 in Burns.
- When is the last frost in Portland, Oregon?
- Portland's average last spring frost is February 25, and by March 21 the chance of a later frost drops to 10%. Its first fall frost averages December 1, giving a 280-day growing season (NOAA station Portland Kgw-Tv, OR).
- When should you plant tomatoes in Oregon?
- Transplant tomatoes in Oregon 1 to 2 weeks after the local average last frost, once nights stay above about 50 °F: Mar 4 – Mar 11 in Portland, Apr 10 – Apr 17 in Salem and Apr 18 – Apr 25 in Eugene. Start seeds indoors 6 to 8 weeks before the last frost.
- When is the first frost in Oregon?
- The average first fall frost in Oregon arrives between September 18 and November 30 for most ZIP codes, with a median of October 28. Harvest tender crops such as tomatoes, peppers and basil before then or cover them on cold nights.
- How long is the growing season in Oregon?
- The frost-free growing season in Oregon lasts about 105 to 270 days for most ZIP codes, with a median of 196 days, from 85 days in Burns to 303 days in Beaverton.
Frost data: NOAA National Centers for Environmental Information, 1991–2020 U.S. Climate Normals (32 °F freeze dates by probability). ZIP code and city locations and populations: U.S. Census Bureau Gazetteer files and Vintage 2024 population estimates. Planting windows are general rules of thumb. PlantoScan is not affiliated with or endorsed by these agencies.