Portland, Oregon: planting zone & frost dates
Portland is in USDA plant hardiness zone 9a, where the average coldest winter night reaches 20 to 25°F (-6.7 to -3.9°C). The typical last spring frost is around Mar 6 and the first fall frost around Nov 22.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 21 | Nov 10 |
| Typical planning date (30% risk) | Mar 6 | Nov 22 |
| Median (50%) | Feb 25 | Dec 1 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station PORTLAND KGW-TV, OR (USC00356749), 2.3 mi (3.7 km) from the city center and 3 ft lower than the city center (-1 m). Record used for the 1991–2020 normals: 24 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Portland
Portland spans more than one half-zone. Share of the city's land area by zone (via its 29 ZIP codes): 9a (67%), 8b (33%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Portland and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 97203 | 9a | 8.1% |
| 97219 | 8b | 7.7% |
| 97217 | 9a | 7.4% |
| 97210 | 8b | 6.1% |
| 97220 | 9a | 5.5% |
| 97211 | 9a | 5.3% |
| 97236 | 9a | 5.2% |
| 97230 | 9a | 5.1% |
| 97218 | 9a | 5.0% |
| 97202 | 9a | 4.7% |
| 97206 | 9a | 4.4% |
| 97266 | 9a | 4.4% |
| 97231 | 8b | 3.4% |
| 97213 | 8b | 3.0% |
| 97229 | 8b | 3.0% |
| 97221 | 8b | 2.7% |
| 97239 | 8b | 2.7% |
| 97233 | 9a | 2.3% |
| 97214 | 9a | 2.2% |
| 97212 | 8b | 2.0% |
| 97216 | 9a | 1.9% |
| 97215 | 9a | 1.7% |
| 97201 | 8b | 1.4% |
| 97232 | 9a | 1.4% |
| 97227 | 9a | 1.1% |
| 97209 | 9a | 0.8% |
| 97205 | 8b | 0.7% |
| 97204 | 9a | 0.2% |
| 97208 | 9a | 0.0% |
Vegetable planting calendar for Portland
Dates are counted from the 30%-risk frost dates above (last frost Mar 6, first frost Nov 22). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Jan 9 – Jan 23 | Mar 13 – Mar 27 | — | — |
| Pepper | Dec 26 – Jan 9 | Mar 20 – Apr 3 | — | — |
| Lettuce | Jan 23 – Feb 6 | Feb 20 – Mar 13 | Feb 6 – Mar 20 | Sep 13 – Oct 11 |
| Green Beans | — | — | Mar 13 – Apr 17 | Aug 30 – Sep 13 |
| Sweet Corn | — | — | Mar 13 – Apr 10 | — |
| Zucchini & Summer Squash | Feb 6 – Feb 13 | Mar 13 – Mar 27 | Mar 13 – Apr 3 | Aug 30 – Sep 13 |
| Cucumber | Feb 6 – Feb 13 | Mar 20 – Mar 27 | Mar 13 – Apr 3 | Aug 30 – Sep 13 |
| Carrot | — | — | Feb 13 – Mar 20 | Aug 30 – Sep 13 |
| Onion | Dec 12 – Dec 26 | Feb 6 – Feb 20 | — | — |
| Potato | — | Feb 6 – Feb 27 | — | — |
| Basil | Jan 23 – Feb 6 | Mar 20 – Apr 3 | Mar 20 – Apr 10 | — |
| Spinach | — | — | Jan 23 – Feb 20 | Sep 27 – Oct 25 |
| Kale | Jan 9 – Jan 23 | Feb 6 – Feb 27 | Feb 6 – Feb 27 | Sep 13 – Oct 11 |
| Broccoli | Jan 9 – Jan 23 | Feb 20 – Mar 13 | — | Aug 30 – Sep 13 |
| Peas | — | — | Jan 23 – Feb 13 | Sep 13 – Sep 27 |
| Eggplant | Dec 26 – Jan 9 | Mar 20 – Apr 3 | — | — |
| Cabbage | Jan 9 – Jan 23 | Feb 6 – Feb 20 | — | Aug 30 – Sep 13 |
| Radish | — | — | Jan 30 – Mar 20 | Oct 11 – Nov 8 |
| Strawberry | — | Feb 6 – Feb 27 | — | — |
| Beets | — | — | Feb 13 – Mar 27 | Sep 13 – Sep 27 |
Nearby cities in Oregon
- Beaverton — zone 9a, last frost Apr 11, first frost Oct 29
- Gresham — zone 9a, last frost Mar 27, first frost Nov 9
- Hillsboro — zone 8b, last frost Apr 25, first frost Oct 14
- Salem — zone 8b, last frost Apr 13, first frost Oct 26
- Eugene — zone 8b, last frost Apr 25, first frost Oct 15
- Bend — zone 6b, last frost Jun 14, first frost Sep 12
More: all Oregon cities · other zone 9a cities: San Antonio, TX, Austin, TX, Seattle, WA, Las Vegas, NV, Tucson, AZ, Baton Rouge, LA, Tallahassee, FL, Mobile, AL
Portland gardening questions
When is the last frost in Portland, OR?
Plan around Mar 6. At NOAA's Portland KGW-TV, OR station, 2.3 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Feb 25, and after Mar 21 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Jan 31. Springs here are erratic: 56 days separate the 90% and 10% dates, versus a median of 36 days for cities on this site, so watch the forecast rather than the calendar.
When should I plant tomatoes in Portland, OR?
Start seeds indoors Jan 9 – Jan 23 and set transplants outside Mar 13 – Mar 27, once nights stay above 50°F and the soil is near 60°F. With about 261 frost-free days, frost is not the main limit — fruit set drops when nights stay above about 75°F, so early plantings tend to do best. More: tomato planting dates by zone.
How long is the growing season in Portland?
About 280 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 245 days, and in 1 year in 10 it runs 318 days or more. In fall there is a 10% chance of frost by Nov 10 and a 30% chance by Nov 22. That is the longest of the 8 Oregon cities on this site.
When should I plant a fall garden in Portland?
Count back from the first fall frost (Nov 22): transplant broccoli Aug 30 – Sep 13; sow kale Sep 13 – Oct 11; sow lettuce Sep 13 – Oct 11; sow radishes Oct 11 – Nov 8. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 20. How the math works: succession and fall planting.
Did Portland's hardiness zone change on the 2023 map?
Yes. Most of Portland was zone 8b on the 2012 map and is zone 9a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
Is all of Portland in zone 9a?
No. Zone 9a covers about 67% of the city's land; the rest is in 8b (33%), measured across the city's 29 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.