Frost dates for 97231 — Portland, OR
How Portland compares
- In 8 years out of 10, the last spring frost in Portland falls between March 25 and May 3, a 39-day window. The first fall frost falls between October 3 and November 18.
- The median last frost is the same as the Oregon median of Apr 16.
- Its 190-day growing season is longer than 45% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 31 days later than the zone 8b median of Mar 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8b chart.
- The weather station records an average of 64 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 25 |
| 50% (median) | April 16 |
| 10% (safe for tender plants) | May 3 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 3 |
| 50% (median) | October 23 |
| 90% (late) | November 18 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Portland, OR
Frost dates for 97231 — Portland, OR — last frost Apr 16, first frost Oct 23, zone 8b. whenisthelastfrost.com
When to plant vegetables in Portland, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 22 – Feb 5 | Mar 19 – Apr 2 | — | — |
| Peppers | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Eggplant | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Tomatoes | Feb 19 – Mar 5 | Apr 23 – May 7 | — | — |
| Lettuce | Feb 19 – Mar 5 | Mar 26 – Apr 9 | Mar 19 – Apr 23 | Aug 28 – Sep 25 |
| Kale | Feb 19 – Mar 5 | Mar 19 – Apr 2 | Mar 19 – Apr 2 | Aug 14 – Sep 4 |
| Broccoli | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 17 – Aug 7 |
| Cabbage | Feb 19 – Mar 5 | Mar 26 – Apr 9 | — | Jul 17 – Aug 7 |
| Cauliflower | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 17 – Aug 7 |
| Okra | Mar 5 – Mar 19 | May 7 – May 21 | May 7 – May 21 | — |
| Basil | Mar 5 – Mar 19 | Apr 23 – May 7 | — | — |
| Peas | — | — | Mar 5 – Mar 26 | Jul 31 – Aug 21 |
| Spinach | — | — | Mar 5 – Mar 26 | Aug 28 – Sep 18 |
| Radishes | — | — | Mar 12 – Apr 23 | Sep 11 – Oct 2 |
| Cucumbers | Mar 19 – Mar 26 | Apr 30 – May 7 | Apr 23 – May 7 | Aug 7 – Aug 21 |
| Zucchini & Summer Squash | Mar 19 – Mar 26 | — | Apr 23 – May 7 | Aug 14 – Aug 28 |
| Winter Squash & Pumpkins | Mar 19 – Mar 26 | — | Apr 23 – May 7 | — |
| Melons & Watermelon | Mar 19 – Mar 26 | Apr 30 – May 14 | — | — |
| Carrots | — | — | Mar 26 – Apr 23 | Jul 31 – Aug 14 |
| Beets | — | — | Mar 26 – Apr 23 | Aug 14 – Aug 28 |
| Potatoes | — | — | Mar 26 – Apr 16 | — |
| Swiss Chard | — | — | Apr 2 – Apr 30 | Aug 14 – Aug 28 |
| Cilantro | — | — | Apr 2 – Apr 23 | Aug 28 – Sep 18 |
| Green Beans | — | — | Apr 23 – May 14 | Aug 7 – Aug 21 |
| Sweet Corn | — | — | Apr 23 – May 7 | — |
| Sweet Potatoes | — | Apr 30 – May 21 | — | — |
| Garlic | — | — | — | Oct 9 – Nov 13 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Portland-Hillsboro Ap, OR weather station, 14 km away (elevation 203 ft (62 m)).
ZIP codes in Portland: 97201 97202 97203 97204 97205 97206 97207 97208 97209 97210 97211 97212 97213 97214 97215 97216 97217 97218 97219 97220 97221 97222 97223 97224 97225 97227 97228 97229 97230 97231 97232 97233 97236 97238 97239 97240 97242 97250 97251 97252 97253 97254 97256 97258 97266 97267 97268 97269 97280 97281 97282 97283 97286 97290 97291 97292 97293 97294 97296 97298
Frost dates near Portland
- Scappoose Apr 10 · Nov 2
- North Plains Apr 16 · Oct 23
- Hillsboro Apr 16 · Oct 23
- Beaverton Feb 11 · Dec 5
- Cornelius Apr 16 · Oct 26
- Warren Apr 18 · Nov 7
- Banks Apr 16 · Oct 26
- Saint Helens Apr 18 · Nov 7
Frequently asked questions
When is the last frost in Portland, OR?
The median last spring frost in Portland, OR is April 16. There is still about a 10% chance of frost after May 3, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Portland, OR?
The median first fall frost is October 23, with about a 10% chance of frost before October 3.
How long is the growing season in Portland, OR?
About 190 days between the median last spring frost and first fall frost.
What planting zone is Portland, OR?
Portland, OR is in USDA hardiness zone 8b.