Fall in zone 8bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 98588 (Mason County, 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, Cushman Powerhouse #2, WA (8 miles away).
- Average last spring frostMar 2450% chance of a 32°F freeze after this date
- Average first fall frostNov 1550% chance of a 32°F freeze by this date
- Growing season (frost-free)235 daysmedian, 32°F threshold
- USDA hardiness zone8b15 to 20°F avg. coldest night
Get The Dial for 98588
Frost and freeze alerts from the NWS forecast for 98588, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.
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
56°F 55°F or warmer
24-hour average · latest 55°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Quinault 4 NE (37 mi).
4-inch depth
56°F 55°F or warmer
24-hour average · latest 55°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Quinault 4 NE (37 mi).
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 98588 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 56°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
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 20–Oct 18
- Radish: fall sowing Oct 4–18
- Garlic: fall sowing Oct 4–Nov 1
- Shallot: fall sowing Oct 4–Nov 1
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 15: 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 26 |
| 50% (the "average" last frost) | Mar 24 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 17 |
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 25 |
| 50% (the "average" first frost) | Nov 15 |
| 90% (late: most years have frozen by now) | Dec 8 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 22 | Oct 28 |
| 32°F (freeze) | Mar 24 | Nov 15 |
| 28°F (hard freeze) | Feb 20 | Dec 7 |
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 98588
Dates count from your average last spring frost (Mar 24) and first fall frost (Nov 15). 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 27–Feb 10 | Mar 31–Apr 14 (transplant) | Jul 19–Aug 16 (transplant) |
| Pepper (sweet and hot) | Jan 13–27 | Apr 7–21 (transplant) | Jul 26–Aug 16 (transplant) |
| Eggplant | Jan 13–27 | Apr 7–21 (transplant) | Jul 26–Aug 16 (transplant) |
| Tomatillo | Jan 27–Feb 10 | Mar 31–Apr 14 (transplant) | – |
| Lettuce | Jan 27–Feb 10 | Mar 3–24 (transplant) Feb 24–Apr 7 (sow outdoors) | Sep 20–Oct 11 (transplant) Sep 6–Oct 4 (sowing) |
| Spinach | – | Feb 10–Mar 3 (sow outdoors) | Sep 20–Oct 11 (sowing) |
| Kale | Jan 27–Feb 10 | Feb 24–Mar 10 (transplant) Feb 24–Mar 10 (sow outdoors) | Aug 23–Sep 20 (transplant) Aug 9–Sep 6 (sowing) |
| Collards | Jan 27–Feb 10 | Feb 24–Mar 24 (transplant) Feb 24–Mar 24 (sow outdoors) | Aug 23–Sep 20 (transplant) Aug 9–Sep 6 (sowing) |
| Broccoli | Jan 13–27 | Feb 24–Mar 10 (transplant) | Aug 9–Sep 6 (transplant) |
| Cabbage | Jan 13–27 | Feb 24–Mar 10 (transplant) | Aug 9–Sep 6 (transplant) |
| Cauliflower | Jan 13–27 | Mar 10–24 (transplant) | Aug 9–Sep 6 (transplant) |
| Brussels sprouts | Dec 30–Jan 13 | Feb 24–Mar 10 (transplant) | Jul 26–Aug 16 (transplant) |
| Kohlrabi | Jan 27–Feb 10 | Feb 24–Mar 10 (transplant) Feb 24–Mar 10 (sow outdoors) | Sep 6–20 (sowing) |
| Bok choy / Asian greens | – | Feb 24–Mar 10 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Arugula | – | Feb 24–Mar 24 (sow outdoors) | Sep 20–Oct 18 (sowing) |
| Mustard greens | – | Feb 24–Mar 17 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Swiss chard | Feb 10–24 | Mar 10–31 (transplant) Mar 10–Apr 7 (sow outdoors) | Sep 6–20 (sowing) |
| Beet | – | Feb 24–Mar 24 (sow outdoors) | Sep 6–20 (sowing) |
| Carrot | – | Mar 3–31 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Radish | – | Feb 17–Mar 31 (sow outdoors) | Oct 4–18 (sowing) |
| Turnip | – | Feb 24–Mar 17 (sow outdoors) | Sep 6–20 (sowing) |
| Parsnip | – | Mar 3–24 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 27–Feb 24 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Onion (bulbing) | Dec 30–Jan 13 | Feb 10–24 (transplant) | – |
| Green onion / scallion | – | Feb 10–Mar 10 (sow outdoors) | Sep 6–20 (sowing) |
| Leek | Dec 30–Jan 13 | Feb 24–Mar 10 (transplant) | – |
| Garlic | – | – | Oct 4–Nov 1 (sowing) |
| Shallot | – | Feb 10–24 (transplant) | Oct 4–Nov 1 (sowing) |
| Potato | – | Feb 24–Mar 10 (transplant) | Jul 26–Aug 9 (transplant) |
| Sweet potato | – | Apr 14–28 (transplant) | – |
| Sweet corn | – | Mar 31–Apr 14 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 31–Apr 14 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Bean, pole | – | Mar 31–Apr 14 (sow outdoors) | – |
| Lima bean | – | Apr 7–21 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 14–May 5 (sow outdoors) | – |
| Cucumber | Feb 24–Mar 3 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Summer squash / zucchini | Feb 24–Mar 3 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Winter squash | Feb 24–Mar 3 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | – |
| Pumpkin | – | Mar 31–Apr 14 (sow outdoors) | – |
| Watermelon | Feb 24–Mar 3 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 24–Mar 3 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | – |
| Okra | Feb 10–24 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | – |
| Celery | Dec 30–Jan 13 | Mar 31–Apr 7 (transplant) | – |
| Basil | Feb 10–24 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | – |
| Cilantro | – | Mar 10–Apr 7 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Parsley | Jan 13–27 | Mar 10–24 (transplant) Mar 3–24 (sow outdoors) | – |
| Dill | – | Mar 24–Apr 7 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Sunflower | – | Mar 24–Apr 7 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 24–Mar 10 (transplant) | – |
| Rhubarb (crowns) | – | Feb 24–Mar 10 (transplant) | – |
| Strawberry (plants) | – | Feb 24–Mar 10 (transplant) | Sep 6–Oct 4 (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: Cushman Powerhouse #2, WA (NOAA GHCN-Daily ID USC00451939), elevation 21 ft, 8.0 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Shelton Sanderson Fld, WA | 15 mi | Apr 27 | Oct 16 |
| Bremerton, WA | 18 mi | Mar 29 | Nov 14 |
| Tacoma Narrows AP, WA | 25 mi | Mar 11 | Nov 21 |
The average last-frost dates of these stations span 47 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98588
When is the last frost in 98588?
The average (50% chance) last spring freeze of 32°F for ZIP 98588 is March 24. For a more cautious planting date, use April 17, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98588?
The average first fall freeze is November 15. In 1 year in 10 it comes by October 25.
What hardiness zone is 98588?
ZIP 98588 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 98588 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
98555 98528 Belfair 98592 Union 98548 Hoodsport 98546 Grapeview 98524 Grapeview 98380 Seabeck 98394 Key Center
Other ZIP codes in Mason County
98524 98528 98546 98548 98555 98560 98584 98592 All Mason County frost dates · Washington frost dates
Never miss a frost: get The Dial
Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.