Fall in zone 9aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 98148 (Burien, WA)
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, Seattle Tacoma Intl AP, WA (1 miles away).
- Average last spring frostMar 250% chance of a 32°F freeze after this date
- Average first fall frostNov 2350% chance of a 32°F freeze by this date
- Growing season (frost-free)266 daysmedian, 32°F threshold
- USDA hardiness zone9a20 to 25°F avg. coldest night
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Frost and freeze alerts from the NWS forecast for 98148, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
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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 98148 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
- Lettuce: fall transplant Sep 28–Oct 19
- Spinach: fall sowing Sep 28–Oct 19
- Arugula: fall sowing Sep 28–Oct 26
- Radish: fall sowing Oct 12–26
- Garlic: fall sowing Oct 12–Nov 9
- Shallot: fall sowing Oct 12–Nov 9
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 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) | Feb 5 |
| 50% (the "average" last frost) | Mar 2 |
| 10% (cautious: only 1 year in 10 freezes later) | Mar 23 |
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) | Nov 6 |
| 50% (the "average" first frost) | Nov 23 |
| 90% (late: most years have frozen by now) | Dec 15 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Mar 31 | Nov 7 |
| 32°F (freeze) | Mar 2 | Nov 23 |
| 28°F (hard freeze) | Feb 4 | Dec 10 |
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 98148
Dates count from your average last spring frost (Mar 2) and first fall frost (Nov 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 | Jan 5–19 | Mar 9–23 (transplant) | Jul 27–Aug 24 (transplant) |
| Pepper (sweet and hot) | Dec 22–Jan 5 | Mar 16–30 (transplant) | Aug 3–24 (transplant) |
| Eggplant | Dec 22–Jan 5 | Mar 16–30 (transplant) | Aug 3–24 (transplant) |
| Tomatillo | Jan 5–19 | Mar 9–23 (transplant) | – |
| Lettuce | Jan 5–19 | Feb 9–Mar 2 (transplant) Feb 2–Mar 16 (sow outdoors) | Sep 28–Oct 19 (transplant) Sep 14–Oct 12 (sowing) |
| Spinach | – | Jan 19–Feb 9 (sow outdoors) | Sep 28–Oct 19 (sowing) |
| Kale | Jan 5–19 | Feb 2–16 (transplant) Feb 2–16 (sow outdoors) | Aug 31–Sep 28 (transplant) Aug 17–Sep 14 (sowing) |
| Collards | Jan 5–19 | Feb 2–Mar 2 (transplant) Feb 2–Mar 2 (sow outdoors) | Aug 31–Sep 28 (transplant) Aug 17–Sep 14 (sowing) |
| Broccoli | Dec 22–Jan 5 | Feb 2–16 (transplant) | Aug 17–Sep 14 (transplant) |
| Cabbage | Dec 22–Jan 5 | Feb 2–16 (transplant) | Aug 17–Sep 14 (transplant) |
| Cauliflower | Dec 22–Jan 5 | Feb 16–Mar 2 (transplant) | Aug 17–Sep 14 (transplant) |
| Brussels sprouts | Dec 8–22 | Feb 2–16 (transplant) | Aug 3–24 (transplant) |
| Kohlrabi | Jan 5–19 | Feb 2–16 (transplant) Feb 2–16 (sow outdoors) | Sep 14–28 (sowing) |
| Bok choy / Asian greens | – | Feb 2–16 (sow outdoors) | Sep 28–Oct 12 (sowing) |
| Arugula | – | Feb 2–Mar 2 (sow outdoors) | Sep 28–Oct 26 (sowing) |
| Mustard greens | – | Feb 2–23 (sow outdoors) | Sep 28–Oct 12 (sowing) |
| Swiss chard | Jan 19–Feb 2 | Feb 16–Mar 9 (transplant) Feb 16–Mar 16 (sow outdoors) | Sep 14–28 (sowing) |
| Beet | – | Feb 2–Mar 2 (sow outdoors) | Sep 14–28 (sowing) |
| Carrot | – | Feb 9–Mar 9 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Radish | – | Jan 26–Mar 9 (sow outdoors) | Oct 12–26 (sowing) |
| Turnip | – | Feb 2–23 (sow outdoors) | Sep 14–28 (sowing) |
| Parsnip | – | Feb 9–Mar 2 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 5–Feb 2 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Onion (bulbing) | Dec 8–22 | Jan 19–Feb 2 (transplant) | – |
| Green onion / scallion | – | Jan 19–Feb 16 (sow outdoors) | Sep 14–28 (sowing) |
| Leek | Dec 8–22 | Feb 2–16 (transplant) | – |
| Garlic | – | – | Oct 12–Nov 9 (sowing) |
| Shallot | – | Jan 19–Feb 2 (transplant) | Oct 12–Nov 9 (sowing) |
| Potato | – | Feb 2–16 (transplant) | Aug 3–17 (transplant) |
| Sweet potato | – | Mar 23–Apr 6 (transplant) | – |
| Sweet corn | – | Mar 9–23 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 9–23 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Bean, pole | – | Mar 9–23 (sow outdoors) | – |
| Lima bean | – | Mar 16–30 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 23–Apr 13 (sow outdoors) | – |
| Cucumber | Feb 2–9 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Summer squash / zucchini | Feb 2–9 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Winter squash | Feb 2–9 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | – |
| Pumpkin | – | Mar 9–23 (sow outdoors) | – |
| Watermelon | Feb 2–9 | Mar 16–30 (transplant) Mar 16–30 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 2–9 | Mar 16–30 (transplant) Mar 16–30 (sow outdoors) | – |
| Okra | Jan 19–Feb 2 | Mar 16–30 (transplant) Mar 16–30 (sow outdoors) | – |
| Celery | Dec 8–22 | Mar 9–16 (transplant) | – |
| Basil | Jan 19–Feb 2 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | – |
| Cilantro | – | Feb 16–Mar 16 (sow outdoors) | Sep 28–Oct 12 (sowing) |
| Parsley | Dec 22–Jan 5 | Feb 16–Mar 2 (transplant) Feb 9–Mar 2 (sow outdoors) | – |
| Dill | – | Mar 2–16 (sow outdoors) | Sep 28–Oct 12 (sowing) |
| Sunflower | – | Mar 2–16 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 2–16 (transplant) | – |
| Rhubarb (crowns) | – | Feb 2–16 (transplant) | – |
| Strawberry (plants) | – | Feb 2–16 (transplant) | Sep 14–Oct 12 (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: Seattle Tacoma Intl AP, WA (NOAA GHCN-Daily ID USW00024233), elevation 370 ft, 0.6 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Kent, WA | 4 mi | Mar 20 | Nov 10 |
| Seattle Boeing Fld, WA | 6 mi | Mar 13 | Nov 17 |
| Renton Muni AP, WA | 6 mi | Mar 13 | Nov 16 |
The average last-frost dates of these stations span 18 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98148
When is the last frost in 98148?
The average (50% chance) last spring freeze of 32°F for ZIP 98148 is March 2. For a more cautious planting date, use March 23, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98148?
The average first fall freeze is November 23. In 1 year in 10 it comes by November 6.
What hardiness zone is 98148?
ZIP 98148 is in USDA zone 9a (20 to 25°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 98148 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
98158 SeaTac 98166 Burien 98188 Tukwila 98168 Tukwila 98198 Des Moines 98146 Burien 98032 Kent 98178 Bryn Mawr-Skyway
Other ZIP codes in King County
98001 98002 98003 98004 98005 98006 98007 98008 98010 98011 98014 98019 98022 98023 98024 98025 98027 98028 98029 98030 98031 98032 98033 98034 All King County frost dates · Washington 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.