Fall in zone 6bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 98856 (Twisp, 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, Winthrop 1 WSW, WA (10 miles away).
- Average last spring frostMay 1550% chance of a 32°F freeze after this date
- Average first fall frostSep 2250% chance of a 32°F freeze by this date
- Growing season (frost-free)127 daysmedian, 32°F threshold
- USDA hardiness zone6b-5 to 0°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
Estimate Not a measurement at this ZIP: distance-weighted average of Darrington 21 NNE (56 mi).
4-inch depth
50°F 50–55°F
24-hour average · latest 50°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Darrington 21 NNE (56 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 98856 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 50°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically mid-April to mid-May).
Fertilizer window
Lawn region: Mountain West and High Plains. Timing only; always follow the product label.
- Kentucky bluegrass (cool-season): Early fall: Around Labor Day (late August–September); Late fall: Late October–November, before the ground freezes; Late spring: Optional around Memorial Day. Avoid: Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
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 30 |
| 50% (the "average" last frost) | May 15 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 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) | Sep 10 |
| 50% (the "average" first frost) | Sep 22 |
| 90% (late: most years have frozen by now) | Oct 2 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jun 1 | Sep 9 |
| 32°F (freeze) | May 15 | Sep 22 |
| 28°F (hard freeze) | May 1 | Oct 3 |
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 98856
Dates count from your average last spring frost (May 15) and first fall frost (Sep 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 20–Apr 3 | May 22–Jun 5 (transplant) | – |
| Pepper (sweet and hot) | Mar 6–20 | May 29–Jun 12 (transplant) | – |
| Eggplant | Mar 6–20 | May 29–Jun 12 (transplant) | – |
| Tomatillo | Mar 20–Apr 3 | May 22–Jun 5 (transplant) | – |
| Lettuce | Mar 20–Apr 3 | Apr 24–May 15 (transplant) Apr 17–May 29 (sow outdoors) | Jul 28–Aug 18 (transplant) Jul 14–Aug 11 (sowing) |
| Spinach | – | Apr 3–24 (sow outdoors) | Jul 28–Aug 18 (sowing) |
| Kale | Mar 20–Apr 3 | Apr 17–May 1 (transplant) Apr 17–May 1 (sow outdoors) | Jun 30–Jul 28 (transplant) Jun 16–Jul 14 (sowing) |
| Collards | Mar 20–Apr 3 | Apr 17–May 15 (transplant) Apr 17–May 15 (sow outdoors) | Jun 30–Jul 28 (transplant) Jun 16–Jul 14 (sowing) |
| Broccoli | Mar 6–20 | Apr 17–May 1 (transplant) | Jun 16–Jul 14 (transplant) |
| Cabbage | Mar 6–20 | Apr 17–May 1 (transplant) | Jun 16–Jul 14 (transplant) |
| Cauliflower | Mar 6–20 | May 1–15 (transplant) | Jun 16–Jul 14 (transplant) |
| Brussels sprouts | Feb 20–Mar 6 | Apr 17–May 1 (transplant) | Jun 2–23 (transplant) |
| Kohlrabi | Mar 20–Apr 3 | Apr 17–May 1 (transplant) Apr 17–May 1 (sow outdoors) | Jul 14–28 (sowing) |
| Bok choy / Asian greens | – | Apr 17–May 1 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Arugula | – | Apr 17–May 15 (sow outdoors) | Jul 28–Aug 25 (sowing) |
| Mustard greens | – | Apr 17–May 8 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Swiss chard | Apr 3–17 | May 1–22 (transplant) May 1–29 (sow outdoors) | Jul 14–28 (sowing) |
| Beet | – | Apr 17–May 15 (sow outdoors) | Jul 14–28 (sowing) |
| Carrot | – | Apr 24–May 22 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Radish | – | Apr 10–May 22 (sow outdoors) | Aug 11–25 (sowing) |
| Turnip | – | Apr 17–May 8 (sow outdoors) | Jul 14–28 (sowing) |
| Parsnip | – | Apr 24–May 15 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 20–Apr 17 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Onion (bulbing) | Feb 20–Mar 6 | Apr 3–17 (transplant) | – |
| Green onion / scallion | – | Apr 3–May 1 (sow outdoors) | Jul 14–28 (sowing) |
| Leek | Feb 20–Mar 6 | Apr 17–May 1 (transplant) | – |
| Garlic | – | – | Aug 11–Sep 8 (sowing) |
| Shallot | – | Apr 3–17 (transplant) | Aug 11–Sep 8 (sowing) |
| Potato | – | Apr 17–May 1 (transplant) | Jun 2–16 (transplant) |
| Sweet potato | – | Jun 5–19 (transplant) | – |
| Sweet corn | – | May 22–Jun 5 (sow outdoors) | – |
| Bean, bush (snap) | – | May 22–Jun 5 (sow outdoors) | – |
| Bean, pole | – | May 22–Jun 5 (sow outdoors) | – |
| Lima bean | – | May 29–Jun 12 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 5–26 (sow outdoors) | – |
| Cucumber | Apr 17–24 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Summer squash / zucchini | Apr 17–24 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Winter squash | Apr 17–24 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Pumpkin | – | May 22–Jun 5 (sow outdoors) | – |
| Watermelon | Apr 17–24 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 17–24 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Okra | Apr 3–17 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Celery | Feb 20–Mar 6 | May 22–29 (transplant) | – |
| Basil | Apr 3–17 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Cilantro | – | May 1–29 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Parsley | Mar 6–20 | May 1–15 (transplant) Apr 24–May 15 (sow outdoors) | – |
| Dill | – | May 15–29 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Sunflower | – | May 15–29 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 17–May 1 (transplant) | – |
| Rhubarb (crowns) | – | Apr 17–May 1 (transplant) | – |
| Strawberry (plants) | – | Apr 17–May 1 (transplant) | Jul 14–Aug 11 (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: Winthrop 1 WSW, WA (NOAA GHCN-Daily ID USC00459376), elevation 1,749 ft, 9.7 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Mazama, WA | 19 mi | May 9 | Sep 29 |
| Methow 2 S, WA | 20 mi | Apr 21 | Oct 15 |
| Stehekin 4 NW, WA | 21 mi | Apr 27 | Oct 17 |
The average last-frost dates of these stations span 25 days, a rough guide to local variation. See data sources & methods.
Frost questions for 98856
When is the last frost in 98856?
The average (50% chance) last spring freeze of 32°F for ZIP 98856 is May 15. For a more cautious planting date, use June 1, when only 1 year in 10 still sees a later freeze.
When is the first frost in 98856?
The average first fall freeze is September 22. In 1 year in 10 it comes by September 10.
What hardiness zone is 98856?
ZIP 98856 is in USDA zone 6b (-5 to 0°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 98856 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
98814 98862 Winthrop 98834 Methow 98852 98816 Chelan 98829 98812 Brewster 98819 Conconully
Other ZIP codes in Okanogan County
98812 98814 98819 98827 98829 98833 98834 98840 98841 98844 98846 98849 98855 98859 98862 99116 99124 99155 All Okanogan 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.