Fall in zone 6bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 99157 (Northport, 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, Northport, WA (2 miles away).
- Average last spring frostMay 850% chance of a 32°F freeze after this date
- Average first fall frostOct 150% chance of a 32°F freeze by this date
- Growing season (frost-free)143 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
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 99157 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 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 27 |
| 50% (the "average" last frost) | May 8 |
| 10% (cautious: only 1 year in 10 freezes later) | May 26 |
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 15 |
| 50% (the "average" first frost) | Oct 1 |
| 90% (late: most years have frozen by now) | Oct 14 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 27 | Sep 19 |
| 32°F (freeze) | May 8 | Oct 1 |
| 28°F (hard freeze) | Apr 26 | Oct 13 |
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 99157
Dates count from your average last spring frost (May 8) and first fall frost (Oct 1). 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 13–27 | May 15–29 (transplant) | – |
| Pepper (sweet and hot) | Feb 27–Mar 13 | May 22–Jun 5 (transplant) | – |
| Eggplant | Feb 27–Mar 13 | May 22–Jun 5 (transplant) | – |
| Tomatillo | Mar 13–27 | May 15–29 (transplant) | – |
| Lettuce | Mar 13–27 | Apr 17–May 8 (transplant) Apr 10–May 22 (sow outdoors) | Aug 6–27 (transplant) Jul 23–Aug 20 (sowing) |
| Spinach | – | Mar 27–Apr 17 (sow outdoors) | Aug 6–27 (sowing) |
| Kale | Mar 13–27 | Apr 10–24 (transplant) Apr 10–24 (sow outdoors) | Jul 9–Aug 6 (transplant) Jun 25–Jul 23 (sowing) |
| Collards | Mar 13–27 | Apr 10–May 8 (transplant) Apr 10–May 8 (sow outdoors) | Jul 9–Aug 6 (transplant) Jun 25–Jul 23 (sowing) |
| Broccoli | Feb 27–Mar 13 | Apr 10–24 (transplant) | Jun 25–Jul 23 (transplant) |
| Cabbage | Feb 27–Mar 13 | Apr 10–24 (transplant) | Jun 25–Jul 23 (transplant) |
| Cauliflower | Feb 27–Mar 13 | Apr 24–May 8 (transplant) | Jun 25–Jul 23 (transplant) |
| Brussels sprouts | Feb 13–27 | Apr 10–24 (transplant) | Jun 11–Jul 2 (transplant) |
| Kohlrabi | Mar 13–27 | Apr 10–24 (transplant) Apr 10–24 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Bok choy / Asian greens | – | Apr 10–24 (sow outdoors) | Aug 6–20 (sowing) |
| Arugula | – | Apr 10–May 8 (sow outdoors) | Aug 6–Sep 3 (sowing) |
| Mustard greens | – | Apr 10–May 1 (sow outdoors) | Aug 6–20 (sowing) |
| Swiss chard | Mar 27–Apr 10 | Apr 24–May 15 (transplant) Apr 24–May 22 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Beet | – | Apr 10–May 8 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Carrot | – | Apr 17–May 15 (sow outdoors) | Jul 9–23 (sowing) |
| Radish | – | Apr 3–May 15 (sow outdoors) | Aug 20–Sep 3 (sowing) |
| Turnip | – | Apr 10–May 1 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Parsnip | – | Apr 17–May 8 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 13–Apr 10 (sow outdoors) | Jul 9–23 (sowing) |
| Onion (bulbing) | Feb 13–27 | Mar 27–Apr 10 (transplant) | – |
| Green onion / scallion | – | Mar 27–Apr 24 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Leek | Feb 13–27 | Apr 10–24 (transplant) | – |
| Garlic | – | – | Aug 20–Sep 17 (sowing) |
| Shallot | – | Mar 27–Apr 10 (transplant) | Aug 20–Sep 17 (sowing) |
| Potato | – | Apr 10–24 (transplant) | Jun 11–25 (transplant) |
| Sweet potato | – | May 29–Jun 12 (transplant) | – |
| Sweet corn | – | May 15–29 (sow outdoors) | – |
| Bean, bush (snap) | – | May 15–29 (sow outdoors) | – |
| Bean, pole | – | May 15–29 (sow outdoors) | – |
| Lima bean | – | May 22–Jun 5 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 29–Jun 19 (sow outdoors) | – |
| Cucumber | Apr 10–17 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Summer squash / zucchini | Apr 10–17 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Winter squash | Apr 10–17 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Pumpkin | – | May 15–29 (sow outdoors) | – |
| Watermelon | Apr 10–17 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 10–17 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Okra | Mar 27–Apr 10 | May 22–Jun 5 (transplant) May 22–Jun 5 (sow outdoors) | – |
| Celery | Feb 13–27 | May 15–22 (transplant) | – |
| Basil | Mar 27–Apr 10 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Cilantro | – | Apr 24–May 22 (sow outdoors) | Aug 6–20 (sowing) |
| Parsley | Feb 27–Mar 13 | Apr 24–May 8 (transplant) Apr 17–May 8 (sow outdoors) | – |
| Dill | – | May 8–22 (sow outdoors) | Aug 6–20 (sowing) |
| Sunflower | – | May 8–22 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 10–24 (transplant) | – |
| Rhubarb (crowns) | – | Apr 10–24 (transplant) | – |
| Strawberry (plants) | – | Apr 10–24 (transplant) | Jul 23–Aug 20 (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: Northport, WA (NOAA GHCN-Daily ID USC00455946), elevation 1,497 ft, 2.0 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Boundary Dam, WA | 21 mi | May 4 | Oct 4 |
| Colville, WA | 25 mi | May 2 | Oct 2 |
| Chewelah, WA | 45 mi | May 16 | Sep 15 |
The average last-frost dates of these stations span 14 days, a rough guide to local variation. See data sources & methods.
Frost questions for 99157
When is the last frost in 99157?
The average (50% chance) last spring freeze of 32°F for ZIP 99157 is May 8. For a more cautious planting date, use May 26, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99157?
The average first fall freeze is October 1. In 1 year in 10 it comes by September 15.
What hardiness zone is 99157?
ZIP 99157 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 99157 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
99126 99114 Colville 99152 Metaline 99151 Marcus 99141 Kettle Falls 99146 Laurier 99160 Orient 99139 Ione
Other ZIP codes in Stevens County
99013 99034 99040 99101 99109 99110 99114 99126 99129 99131 99137 99148 99151 99167 99173 99181 All Stevens County frost dates · Washington frost dates
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- Freeze alerts
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- 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.