Frost dates for ZIP 98174 (Seattle, 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 Boeing Fld, WA (5 miles away).
- Average last spring frostMar 1350% chance of a 32°F freeze after this date
- Average first fall frostNov 1750% chance of a 32°F freeze by this date
- Growing season (frost-free)247 daysmedian, 32°F threshold
- USDA hardiness zone9a20 to 25°F avg. coldest night
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This week in your yard
As of Oct 17, 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 98174 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
- Arugula: fall sowing Sep 22–Oct 20
- Radish: fall sowing Oct 6–20
- Garlic: fall sowing Oct 6–Nov 3
- Shallot: fall sowing Oct 6–Nov 3
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 17: 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 20 |
| 50% (the "average" last frost) | Mar 13 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 1 |
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 1 |
| 50% (the "average" first frost) | Nov 17 |
| 90% (late: most years have frozen by now) | Dec 6 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 3 | Oct 31 |
| 32°F (freeze) | Mar 13 | Nov 17 |
| 28°F (hard freeze) | Feb 18 | Dec 2 |
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 98174
Dates count from your average last spring frost (Mar 13) and first fall frost (Nov 17). 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 16–30 | Mar 20–Apr 3 (transplant) | Jul 21–Aug 18 (transplant) |
| Pepper (sweet and hot) | Jan 2–16 | Mar 27–Apr 10 (transplant) | Jul 28–Aug 18 (transplant) |
| Eggplant | Jan 2–16 | Mar 27–Apr 10 (transplant) | Jul 28–Aug 18 (transplant) |
| Tomatillo | Jan 16–30 | Mar 20–Apr 3 (transplant) | – |
| Lettuce | Jan 16–30 | Feb 20–Mar 13 (transplant) Feb 13–Mar 27 (sow outdoors) | Sep 22–Oct 13 (transplant) Sep 8–Oct 6 (sowing) |
| Spinach | – | Jan 30–Feb 20 (sow outdoors) | Sep 22–Oct 13 (sowing) |
| Kale | Jan 16–30 | Feb 13–27 (transplant) Feb 13–27 (sow outdoors) | Aug 25–Sep 22 (transplant) Aug 11–Sep 8 (sowing) |
| Collards | Jan 16–30 | Feb 13–Mar 13 (transplant) Feb 13–Mar 13 (sow outdoors) | Aug 25–Sep 22 (transplant) Aug 11–Sep 8 (sowing) |
| Broccoli | Jan 2–16 | Feb 13–27 (transplant) | Aug 11–Sep 8 (transplant) |
| Cabbage | Jan 2–16 | Feb 13–27 (transplant) | Aug 11–Sep 8 (transplant) |
| Cauliflower | Jan 2–16 | Feb 27–Mar 13 (transplant) | Aug 11–Sep 8 (transplant) |
| Brussels sprouts | Dec 19–Jan 2 | Feb 13–27 (transplant) | Jul 28–Aug 18 (transplant) |
| Kohlrabi | Jan 16–30 | Feb 13–27 (transplant) Feb 13–27 (sow outdoors) | Sep 8–22 (sowing) |
| Bok choy / Asian greens | – | Feb 13–27 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Arugula | – | Feb 13–Mar 13 (sow outdoors) | Sep 22–Oct 20 (sowing) |
| Mustard greens | – | Feb 13–Mar 6 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Swiss chard | Jan 30–Feb 13 | Feb 27–Mar 20 (transplant) Feb 27–Mar 27 (sow outdoors) | Sep 8–22 (sowing) |
| Beet | – | Feb 13–Mar 13 (sow outdoors) | Sep 8–22 (sowing) |
| Carrot | – | Feb 20–Mar 20 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Radish | – | Feb 6–Mar 20 (sow outdoors) | Oct 6–20 (sowing) |
| Turnip | – | Feb 13–Mar 6 (sow outdoors) | Sep 8–22 (sowing) |
| Parsnip | – | Feb 20–Mar 13 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 16–Feb 13 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Onion (bulbing) | Dec 19–Jan 2 | Jan 30–Feb 13 (transplant) | – |
| Green onion / scallion | – | Jan 30–Feb 27 (sow outdoors) | Sep 8–22 (sowing) |
| Leek | Dec 19–Jan 2 | Feb 13–27 (transplant) | – |
| Garlic | – | – | Oct 6–Nov 3 (sowing) |
| Shallot | – | Jan 30–Feb 13 (transplant) | Oct 6–Nov 3 (sowing) |
| Potato | – | Feb 13–27 (transplant) | Jul 28–Aug 11 (transplant) |
| Sweet potato | – | Apr 3–17 (transplant) | – |
| Sweet corn | – | Mar 20–Apr 3 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 20–Apr 3 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Bean, pole | – | Mar 20–Apr 3 (sow outdoors) | – |
| Lima bean | – | Mar 27–Apr 10 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 3–24 (sow outdoors) | – |
| Cucumber | Feb 13–20 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Summer squash / zucchini | Feb 13–20 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Winter squash | Feb 13–20 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | – |
| Pumpkin | – | Mar 20–Apr 3 (sow outdoors) | – |
| Watermelon | Feb 13–20 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 13–20 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | – |
| Okra | Jan 30–Feb 13 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | – |
| Celery | Dec 19–Jan 2 | Mar 20–27 (transplant) | – |
| Basil | Jan 30–Feb 13 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | – |
| Cilantro | – | Feb 27–Mar 27 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Parsley | Jan 2–16 | Feb 27–Mar 13 (transplant) Feb 20–Mar 13 (sow outdoors) | – |
| Dill | – | Mar 13–27 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Sunflower | – | Mar 13–27 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 13–27 (transplant) | – |
| Rhubarb (crowns) | – | Feb 13–27 (transplant) | – |
| Strawberry (plants) | – | Feb 13–27 (transplant) | Sep 8–Oct 6 (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 Boeing Fld, WA (NOAA GHCN-Daily ID USW00024234), elevation 20 ft, 5.4 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Seattle Sand Pt Wsfo, WA | 7 mi | Mar 8 | Nov 23 |
| Renton Muni AP, WA | 10 mi | Mar 13 | Nov 16 |
| Seattle Tacoma Intl AP, WA | 11 mi | Mar 2 | Nov 23 |
The average last-frost dates of these stations span 11 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98174
When is the last frost in 98174?
The average (50% chance) last spring freeze of 32°F for ZIP 98174 is March 13. For a more cautious planting date, use April 1, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98174?
The average first fall freeze is November 17. In 1 year in 10 it comes by November 1.
What hardiness zone is 98174?
ZIP 98174 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 98174 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
98154 Seattle 98164 Seattle 98104 Seattle 98101 Seattle 98121 Seattle 98134 Seattle 98109 Seattle 98122 Seattle
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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