Fall in zone 8bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 97123 (Hillsboro, OR)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Portland-hillsboro AP, OR (7 miles away).
- Average last spring frostApr 1650% chance of a 32°F freeze after this date
- Average first fall frostOct 2350% chance of a 32°F freeze by this date
- Growing season (frost-free)191 daysmedian, 32°F threshold
- USDA hardiness zone8b15 to 20°F avg. coldest night
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This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
No soil station with a fresh reading within 62 miles.
4-inch depth
No soil station with a fresh reading within 62 miles.
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 97123 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
No soil reading near this ZIP. Typical extension timing for your region: spring March to April.
Fertilizer window
Lawn region: Pacific Northwest (west of the Cascades). Timing only; always follow the product label.
- Perennial ryegrass (cool-season): Early fall: September; Late fall: October–November; Overseeded Bermuda: Light feeding once the winter rye is established, if needed. Avoid: Summer feeding.
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Oct 23: skip heavy pruning in the 6–8 weeks before it, because new growth may not harden off in time.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Mar 25 |
| 50% (the "average" last frost) | Apr 16 |
| 10% (cautious: only 1 year in 10 freezes later) | May 3 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Oct 3 |
| 50% (the "average" first frost) | Oct 23 |
| 90% (late: most years have frozen by now) | Nov 18 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 5 | Oct 6 |
| 32°F (freeze) | Apr 16 | Oct 23 |
| 28°F (hard freeze) | Mar 13 | Nov 12 |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 97123
Dates count from your average last spring frost (Apr 16) and first fall frost (Oct 23). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Feb 19–Mar 5 | Apr 23–May 7 (transplant) | – |
| Pepper (sweet and hot) | Feb 5–19 | Apr 30–May 14 (transplant) | – |
| Eggplant | Feb 5–19 | Apr 30–May 14 (transplant) | – |
| Tomatillo | Feb 19–Mar 5 | Apr 23–May 7 (transplant) | – |
| Lettuce | Feb 19–Mar 5 | Mar 26–Apr 16 (transplant) Mar 19–Apr 30 (sow outdoors) | Aug 28–Sep 18 (transplant) Aug 14–Sep 11 (sowing) |
| Spinach | – | Mar 5–26 (sow outdoors) | Aug 28–Sep 18 (sowing) |
| Kale | Feb 19–Mar 5 | Mar 19–Apr 2 (transplant) Mar 19–Apr 2 (sow outdoors) | Jul 31–Aug 28 (transplant) Jul 17–Aug 14 (sowing) |
| Collards | Feb 19–Mar 5 | Mar 19–Apr 16 (transplant) Mar 19–Apr 16 (sow outdoors) | Jul 31–Aug 28 (transplant) Jul 17–Aug 14 (sowing) |
| Broccoli | Feb 5–19 | Mar 19–Apr 2 (transplant) | Jul 17–Aug 14 (transplant) |
| Cabbage | Feb 5–19 | Mar 19–Apr 2 (transplant) | Jul 17–Aug 14 (transplant) |
| Cauliflower | Feb 5–19 | Apr 2–16 (transplant) | Jul 17–Aug 14 (transplant) |
| Brussels sprouts | Jan 22–Feb 5 | Mar 19–Apr 2 (transplant) | Jul 3–24 (transplant) |
| Kohlrabi | Feb 19–Mar 5 | Mar 19–Apr 2 (transplant) Mar 19–Apr 2 (sow outdoors) | Aug 14–28 (sowing) |
| Bok choy / Asian greens | – | Mar 19–Apr 2 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Arugula | – | Mar 19–Apr 16 (sow outdoors) | Aug 28–Sep 25 (sowing) |
| Mustard greens | – | Mar 19–Apr 9 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Swiss chard | Mar 5–19 | Apr 2–23 (transplant) Apr 2–30 (sow outdoors) | Aug 14–28 (sowing) |
| Beet | – | Mar 19–Apr 16 (sow outdoors) | Aug 14–28 (sowing) |
| Carrot | – | Mar 26–Apr 23 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Radish | – | Mar 12–Apr 23 (sow outdoors) | Sep 11–25 (sowing) |
| Turnip | – | Mar 19–Apr 9 (sow outdoors) | Aug 14–28 (sowing) |
| Parsnip | – | Mar 26–Apr 16 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 19–Mar 19 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Onion (bulbing) | Jan 22–Feb 5 | Mar 5–19 (transplant) | – |
| Green onion / scallion | – | Mar 5–Apr 2 (sow outdoors) | Aug 14–28 (sowing) |
| Leek | Jan 22–Feb 5 | Mar 19–Apr 2 (transplant) | – |
| Garlic | – | – | Sep 11–Oct 9 (sowing) |
| Shallot | – | Mar 5–19 (transplant) | Sep 11–Oct 9 (sowing) |
| Potato | – | Mar 19–Apr 2 (transplant) | Jul 3–17 (transplant) |
| Sweet potato | – | May 7–21 (transplant) | – |
| Sweet corn | – | Apr 23–May 7 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 23–May 7 (sow outdoors) | – |
| Bean, pole | – | Apr 23–May 7 (sow outdoors) | – |
| Lima bean | – | Apr 30–May 14 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 7–28 (sow outdoors) | – |
| Cucumber | Mar 19–26 | Apr 23–May 7 (transplant) Apr 23–May 7 (sow outdoors) | – |
| Summer squash / zucchini | Mar 19–26 | Apr 23–May 7 (transplant) Apr 23–May 7 (sow outdoors) | – |
| Winter squash | Mar 19–26 | Apr 23–May 7 (transplant) Apr 23–May 7 (sow outdoors) | – |
| Pumpkin | – | Apr 23–May 7 (sow outdoors) | – |
| Watermelon | Mar 19–26 | Apr 30–May 14 (transplant) Apr 30–May 14 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 19–26 | Apr 30–May 14 (transplant) Apr 30–May 14 (sow outdoors) | – |
| Okra | Mar 5–19 | Apr 30–May 14 (transplant) Apr 30–May 14 (sow outdoors) | – |
| Celery | Jan 22–Feb 5 | Apr 23–30 (transplant) | – |
| Basil | Mar 5–19 | Apr 23–May 7 (transplant) Apr 23–May 7 (sow outdoors) | – |
| Cilantro | – | Apr 2–30 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Parsley | Feb 5–19 | Apr 2–16 (transplant) Mar 26–Apr 16 (sow outdoors) | – |
| Dill | – | Apr 16–30 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Sunflower | – | Apr 16–30 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 19–Apr 2 (transplant) | – |
| Rhubarb (crowns) | – | Mar 19–Apr 2 (transplant) | – |
| Strawberry (plants) | – | Mar 19–Apr 2 (transplant) | Aug 14–Sep 11 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: Portland-hillsboro AP, OR (NOAA GHCN-Daily ID USW00094261), elevation 204 ft, 6.8 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Beaverton 2 SSW, OR | 8 mi | Apr 1 | Nov 6 |
| Nature Park-beaverton, OR | 8 mi | Feb 11 | Dec 5 |
| Forest Grove, OR | 8 mi | Apr 16 | Oct 26 |
The average last-frost dates of these stations span 67 days, a rough guide to local variation. See data sources & methods.
Frost questions for 97123
When is the last frost in 97123?
The average (50% chance) last spring freeze of 32°F for ZIP 97123 is April 16. For a more cautious planting date, use May 3, when only 1 year in 10 still sees a later freeze.
When is the first frost in 97123?
The average first fall freeze is October 23. In 1 year in 10 it comes by October 3.
What hardiness zone is 97123?
ZIP 97123 is in USDA zone 8b (15 to 20°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 97123 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
97078 Aloha 97007 Beaverton 97113 Cornelius 97003 Aloha 97006 Beaverton 97140 Sherwood 97132 Newberg 97008 Beaverton
Other ZIP codes in Washington County
97003 97005 97006 97007 97008 97062 97078 97106 97109 97113 97116 97117 97119 97124 97125 97133 97140 97144 97223 97224 97225 97229 All Washington County frost dates · Oregon frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
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Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.