Fall in zone 8aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 98237 (Concrete, 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, Concrete Ppl Fish STN, WA (1 miles away).
- Average last spring frostMar 2850% chance of a 32°F freeze after this date
- Average first fall frostNov 1450% chance of a 32°F freeze by this date
- Growing season (frost-free)229 daysmedian, 32°F threshold
- USDA hardiness zone8a10 to 15°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
50°F 50–55°F
24-hour average · latest 50°F, as of Oct 18, 1:00 AM CDT
Measured at NOAA USCRN station Darrington 21 NNE, 12 mi away. Daily averages: Thu 51°, Fri 50°, Sat 50°.
4-inch depth
50°F 50–55°F
24-hour average · latest 50°F, as of Oct 18, 1:00 AM CDT
Measured at NOAA USCRN station Darrington 21 NNE, 12 mi away. Daily averages: Thu 51°, Fri 50°, Sat 50°.
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 98237 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 50°F at 4 inches. Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically 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
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 14: 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 7 |
| 50% (the "average" last frost) | Mar 28 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 19 |
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 23 |
| 50% (the "average" first frost) | Nov 14 |
| 90% (late: most years have frozen by now) | Dec 4 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 25 | Oct 25 |
| 32°F (freeze) | Mar 28 | Nov 14 |
| 28°F (hard freeze) | Feb 25 | 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 98237
Dates count from your average last spring frost (Mar 28) and first fall frost (Nov 14). 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 31–Feb 14 | Apr 4–18 (transplant) | Jul 18–Aug 15 (transplant) |
| Pepper (sweet and hot) | Jan 17–31 | Apr 11–25 (transplant) | Jul 25–Aug 15 (transplant) |
| Eggplant | Jan 17–31 | Apr 11–25 (transplant) | Jul 25–Aug 15 (transplant) |
| Tomatillo | Jan 31–Feb 14 | Apr 4–18 (transplant) | – |
| Lettuce | Jan 31–Feb 14 | Mar 7–28 (transplant) Feb 28–Apr 11 (sow outdoors) | Sep 19–Oct 10 (transplant) Sep 5–Oct 3 (sowing) |
| Spinach | – | Feb 14–Mar 7 (sow outdoors) | Sep 19–Oct 10 (sowing) |
| Kale | Jan 31–Feb 14 | Feb 28–Mar 14 (transplant) Feb 28–Mar 14 (sow outdoors) | Aug 22–Sep 19 (transplant) Aug 8–Sep 5 (sowing) |
| Collards | Jan 31–Feb 14 | Feb 28–Mar 28 (transplant) Feb 28–Mar 28 (sow outdoors) | Aug 22–Sep 19 (transplant) Aug 8–Sep 5 (sowing) |
| Broccoli | Jan 17–31 | Feb 28–Mar 14 (transplant) | Aug 8–Sep 5 (transplant) |
| Cabbage | Jan 17–31 | Feb 28–Mar 14 (transplant) | Aug 8–Sep 5 (transplant) |
| Cauliflower | Jan 17–31 | Mar 14–28 (transplant) | Aug 8–Sep 5 (transplant) |
| Brussels sprouts | Jan 3–17 | Feb 28–Mar 14 (transplant) | Jul 25–Aug 15 (transplant) |
| Kohlrabi | Jan 31–Feb 14 | Feb 28–Mar 14 (transplant) Feb 28–Mar 14 (sow outdoors) | Sep 5–19 (sowing) |
| Bok choy / Asian greens | – | Feb 28–Mar 14 (sow outdoors) | Sep 19–Oct 3 (sowing) |
| Arugula | – | Feb 28–Mar 28 (sow outdoors) | Sep 19–Oct 17 (sowing) |
| Mustard greens | – | Feb 28–Mar 21 (sow outdoors) | Sep 19–Oct 3 (sowing) |
| Swiss chard | Feb 14–28 | Mar 14–Apr 4 (transplant) Mar 14–Apr 11 (sow outdoors) | Sep 5–19 (sowing) |
| Beet | – | Feb 28–Mar 28 (sow outdoors) | Sep 5–19 (sowing) |
| Carrot | – | Mar 7–Apr 4 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Radish | – | Feb 21–Apr 4 (sow outdoors) | Oct 3–17 (sowing) |
| Turnip | – | Feb 28–Mar 21 (sow outdoors) | Sep 5–19 (sowing) |
| Parsnip | – | Mar 7–28 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 31–Feb 28 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Onion (bulbing) | Jan 3–17 | Feb 14–28 (transplant) | – |
| Green onion / scallion | – | Feb 14–Mar 14 (sow outdoors) | Sep 5–19 (sowing) |
| Leek | Jan 3–17 | Feb 28–Mar 14 (transplant) | – |
| Garlic | – | – | Oct 3–31 (sowing) |
| Shallot | – | Feb 14–28 (transplant) | Oct 3–31 (sowing) |
| Potato | – | Feb 28–Mar 14 (transplant) | Jul 25–Aug 8 (transplant) |
| Sweet potato | – | Apr 18–May 2 (transplant) | – |
| Sweet corn | – | Apr 4–18 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 4–18 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Bean, pole | – | Apr 4–18 (sow outdoors) | – |
| Lima bean | – | Apr 11–25 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 18–May 9 (sow outdoors) | – |
| Cucumber | Feb 28–Mar 7 | Apr 4–18 (transplant) Apr 4–18 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Summer squash / zucchini | Feb 28–Mar 7 | Apr 4–18 (transplant) Apr 4–18 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Winter squash | Feb 28–Mar 7 | Apr 4–18 (transplant) Apr 4–18 (sow outdoors) | – |
| Pumpkin | – | Apr 4–18 (sow outdoors) | – |
| Watermelon | Feb 28–Mar 7 | Apr 11–25 (transplant) Apr 11–25 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 28–Mar 7 | Apr 11–25 (transplant) Apr 11–25 (sow outdoors) | – |
| Okra | Feb 14–28 | Apr 11–25 (transplant) Apr 11–25 (sow outdoors) | – |
| Celery | Jan 3–17 | Apr 4–11 (transplant) | – |
| Basil | Feb 14–28 | Apr 4–18 (transplant) Apr 4–18 (sow outdoors) | – |
| Cilantro | – | Mar 14–Apr 11 (sow outdoors) | Sep 19–Oct 3 (sowing) |
| Parsley | Jan 17–31 | Mar 14–28 (transplant) Mar 7–28 (sow outdoors) | – |
| Dill | – | Mar 28–Apr 11 (sow outdoors) | Sep 19–Oct 3 (sowing) |
| Sunflower | – | Mar 28–Apr 11 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 28–Mar 14 (transplant) | – |
| Rhubarb (crowns) | – | Feb 28–Mar 14 (transplant) | – |
| Strawberry (plants) | – | Feb 28–Mar 14 (transplant) | Sep 5–Oct 3 (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: Concrete Ppl Fish STN, WA (NOAA GHCN-Daily ID USC00451679), elevation 195 ft, 1.5 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Upper Baker Dam, WA | 8 mi | Apr 24 | Oct 29 |
| Darrington 21 NNE, WA | 12 mi | Apr 16 | Oct 25 |
| Darrington Rs, WA | 20 mi | Apr 16 | Oct 23 |
The average last-frost dates of these stations span 27 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98237
When is the last frost in 98237?
The average (50% chance) last spring freeze of 32°F for ZIP 98237 is March 28. For a more cautious planting date, use April 19, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98237?
The average first fall freeze is November 14. In 1 year in 10 it comes by October 23.
What hardiness zone is 98237?
ZIP 98237 is in USDA zone 8a (10 to 15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 98237 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
98255 Hamilton 98263 Lyman 98244 Kendall 98284 Sedro-Woolley 98267 Marblemount 98274 Big Lake 98235 Clear Lake 98220 Acme
Other ZIP codes in Skagit County
98221 98232 98233 98235 98238 98255 98257 98263 98267 98273 98274 98284 All Skagit County frost dates · Washington frost dates
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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.