Fall in zone 8bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 98643 (Rosburg, 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, Grays Rvr Hatchery, WA (8 miles away).
- Average last spring frostApr 2750% chance of a 32°F freeze after this date
- Average first fall frostOct 2250% chance of a 32°F freeze by this date
- Growing season (frost-free)178 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 98643 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 22: 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) | Apr 2 |
| 50% (the "average" last frost) | Apr 27 |
| 10% (cautious: only 1 year in 10 freezes later) | May 18 |
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 22 |
| 90% (late: most years have frozen by now) | Nov 11 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 17 | Oct 3 |
| 32°F (freeze) | Apr 27 | Oct 22 |
| 28°F (hard freeze) | Mar 25 | 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 98643
Dates count from your average last spring frost (Apr 27) and first fall frost (Oct 22). 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 | Mar 2–16 | May 4–18 (transplant) | – |
| Pepper (sweet and hot) | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Eggplant | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Tomatillo | Mar 2–16 | May 4–18 (transplant) | – |
| Lettuce | Mar 2–16 | Apr 6–27 (transplant) Mar 30–May 11 (sow outdoors) | Aug 27–Sep 17 (transplant) Aug 13–Sep 10 (sowing) |
| Spinach | – | Mar 16–Apr 6 (sow outdoors) | Aug 27–Sep 17 (sowing) |
| Kale | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Collards | Mar 2–16 | Mar 30–Apr 27 (transplant) Mar 30–Apr 27 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Broccoli | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 16–Aug 13 (transplant) |
| Cabbage | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 16–Aug 13 (transplant) |
| Cauliflower | Feb 16–Mar 2 | Apr 13–27 (transplant) | Jul 16–Aug 13 (transplant) |
| Brussels sprouts | Feb 2–16 | Mar 30–Apr 13 (transplant) | Jul 2–23 (transplant) |
| Kohlrabi | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Aug 13–27 (sowing) |
| Bok choy / Asian greens | – | Mar 30–Apr 13 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Arugula | – | Mar 30–Apr 27 (sow outdoors) | Aug 27–Sep 24 (sowing) |
| Mustard greens | – | Mar 30–Apr 20 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Swiss chard | Mar 16–30 | Apr 13–May 4 (transplant) Apr 13–May 11 (sow outdoors) | Aug 13–27 (sowing) |
| Beet | – | Mar 30–Apr 27 (sow outdoors) | Aug 13–27 (sowing) |
| Carrot | – | Apr 6–May 4 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Radish | – | Mar 23–May 4 (sow outdoors) | Sep 10–24 (sowing) |
| Turnip | – | Mar 30–Apr 20 (sow outdoors) | Aug 13–27 (sowing) |
| Parsnip | – | Apr 6–27 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 2–30 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Onion (bulbing) | Feb 2–16 | Mar 16–30 (transplant) | – |
| Green onion / scallion | – | Mar 16–Apr 13 (sow outdoors) | Aug 13–27 (sowing) |
| Leek | Feb 2–16 | Mar 30–Apr 13 (transplant) | – |
| Garlic | – | – | Sep 10–Oct 8 (sowing) |
| Shallot | – | Mar 16–30 (transplant) | Sep 10–Oct 8 (sowing) |
| Potato | – | Mar 30–Apr 13 (transplant) | Jul 2–16 (transplant) |
| Sweet potato | – | May 18–Jun 1 (transplant) | – |
| Sweet corn | – | May 4–18 (sow outdoors) | – |
| Bean, bush (snap) | – | May 4–18 (sow outdoors) | – |
| Bean, pole | – | May 4–18 (sow outdoors) | – |
| Lima bean | – | May 11–25 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 18–Jun 8 (sow outdoors) | – |
| Cucumber | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Summer squash / zucchini | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Winter squash | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Pumpkin | – | May 4–18 (sow outdoors) | – |
| Watermelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Okra | Mar 16–30 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Celery | Feb 2–16 | May 4–11 (transplant) | – |
| Basil | Mar 16–30 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Cilantro | – | Apr 13–May 11 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Parsley | Feb 16–Mar 2 | Apr 13–27 (transplant) Apr 6–27 (sow outdoors) | – |
| Dill | – | Apr 27–May 11 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Sunflower | – | Apr 27–May 11 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Rhubarb (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Strawberry (plants) | – | Mar 30–Apr 13 (transplant) | Aug 13–Sep 10 (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: Grays Rvr Hatchery, WA (NOAA GHCN-Daily ID USC00453333), elevation 100 ft, 8.0 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Naselle 2 ENE, WA | 7 mi | Apr 24 | Oct 20 |
| Astoria Rgnl AP, OR | 14 mi | Mar 26 | Nov 11 |
| Ft Clatsop Natl Mem, OR | 15 mi | Mar 30 | Nov 18 |
The average last-frost dates of these stations span 32 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98643
When is the last frost in 98643?
The average (50% chance) last spring freeze of 32°F for ZIP 98643 is April 27. For a more cautious planting date, use May 18, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98643?
The average first fall freeze is October 22. In 1 year in 10 it comes by October 3.
What hardiness zone is 98643?
ZIP 98643 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 98643 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
98638 Deep River 98621 Grays River 97103 Astoria 98647 Skamokawa Valley 98614 Chinook 98624 Ilwaco 97121 Warrenton 97146 Warrenton
Other ZIP codes in Wahkiakum County
98612 98647 All Wahkiakum County frost dates · Washington frost dates
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- 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.