Beaverton, Oregon: planting zone & frost dates
Beaverton 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 Apr 11 and the first fall frost around Oct 29.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 26 | Oct 19 |
| Typical planning date (30% risk) | Apr 11 | Oct 29 |
| Median (50%) | Apr 1 | Nov 6 |
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 BEAVERTON 2 SSW, OR (USC00350595), 1.6 mi (2.6 km) from the city center and 36 ft higher than the city center (+11 m). Record used for the 1991–2020 normals: 15 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Beaverton
Beaverton spans more than one half-zone. Share of the city's land area by zone (via its 8 ZIP codes): 9a (52%), 8b (48%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Beaverton
Dates are counted from the 30%-risk frost dates above (last frost Apr 11, first frost Oct 29). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 14 – Feb 28 | Apr 18 – May 2 | — | — |
| Pepper | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Lettuce | Feb 28 – Mar 14 | Mar 28 – Apr 18 | Mar 14 – Apr 25 | Aug 20 – Sep 17 |
| Green Beans | — | — | Apr 18 – May 23 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | Apr 18 – May 16 | — |
| Zucchini & Summer Squash | Mar 14 – Mar 21 | Apr 18 – May 2 | Apr 18 – May 9 | Aug 6 – Aug 20 |
| Cucumber | Mar 14 – Mar 21 | Apr 25 – May 2 | Apr 18 – May 9 | Aug 6 – Aug 20 |
| Carrot | — | — | Mar 21 – Apr 25 | Aug 6 – Aug 20 |
| Onion | Jan 17 – Jan 31 | Mar 14 – Mar 28 | — | — |
| Potato | — | Mar 14 – Apr 4 | — | — |
| Basil | Feb 28 – Mar 14 | Apr 25 – May 9 | Apr 25 – May 16 | — |
| Spinach | — | — | Feb 28 – Mar 28 | Sep 3 – Oct 1 |
| Kale | Feb 14 – Feb 28 | Mar 14 – Apr 4 | Mar 14 – Apr 4 | Aug 20 – Sep 17 |
| Broccoli | Feb 14 – Feb 28 | Mar 28 – Apr 18 | — | Aug 6 – Aug 20 |
| Peas | — | — | Feb 28 – Mar 21 | Aug 20 – Sep 3 |
| Eggplant | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Cabbage | Feb 14 – Feb 28 | Mar 14 – Mar 28 | — | Aug 6 – Aug 20 |
| Radish | — | — | Mar 7 – Apr 25 | Sep 17 – Oct 15 |
| Strawberry | — | Mar 14 – Apr 4 | — | — |
| Beets | — | — | Mar 21 – May 2 | Aug 20 – Sep 3 |
Nearby cities in Oregon
- Hillsboro — zone 8b, last frost Apr 25, first frost Oct 14
- Portland — zone 9a, last frost Mar 6, first frost Nov 22
- Gresham — zone 9a, last frost Mar 27, first frost Nov 9
- 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, Portland, OR, Tucson, AZ, Baton Rouge, LA, Tallahassee, FL
Beaverton gardening questions
When is the last frost in Beaverton, OR?
Plan around Apr 11. At NOAA's Beaverton 2 SSW, OR station, 1.6 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 Apr 1, and after Apr 26 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Feb 26. Springs here are erratic: 52 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 Beaverton, OR?
Start seeds indoors Feb 14 – Feb 28 and set transplants outside Apr 18 – May 2, once nights stay above 50°F and the soil is near 60°F. That leaves 201 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Beaverton?
About 222 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 186 days, and in 1 year in 10 it runs 254 days or more. In fall there is a 10% chance of frost by Oct 19 and a 30% chance by Oct 29. That ranks 3rd longest of 8 Oregon cities on this site.
When should I plant a fall garden in Beaverton?
Count back from the first fall frost (Oct 29): transplant broccoli Aug 6 – Aug 20; sow kale Aug 20 – Sep 17; sow lettuce Aug 20 – Sep 17; sow radishes Sep 17 – Oct 15. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 30. How the math works: succession and fall planting.
Did Beaverton's hardiness zone change on the 2023 map?
Yes. Most of Beaverton 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 Beaverton in zone 9a?
No. Zone 9a covers about 52% of the city's land; the rest is in 8b (48%), measured across the city's 8 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.