Fall in zone 6bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 99017 (Lamont, 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, St John, WA (15 miles away).
- Average last spring frostApr 2950% chance of a 32°F freeze after this date
- Average first fall frostOct 450% chance of a 32°F freeze by this date
- Growing season (frost-free)161 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 Below 50°F
24-hour average · latest 50°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Spokane 17 SSW (23 mi), Lind #1 (35 mi), Cook Farm Field D (47 mi).
4-inch depth
51°F 50–55°F
24-hour average · latest 52°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Spokane 17 SSW (23 mi), Lind #1 (35 mi), Cook Farm Field D (47 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 99017 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 51°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 9 |
| 50% (the "average" last frost) | Apr 29 |
| 10% (cautious: only 1 year in 10 freezes later) | May 15 |
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 19 |
| 50% (the "average" first frost) | Oct 4 |
| 90% (late: most years have frozen by now) | Oct 23 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 16 | Sep 23 |
| 32°F (freeze) | Apr 29 | Oct 4 |
| 28°F (hard freeze) | Apr 5 | Oct 20 |
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 99017
Dates count from your average last spring frost (Apr 29) and first fall frost (Oct 4). 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 4–18 | May 6–20 (transplant) | – |
| Pepper (sweet and hot) | Feb 18–Mar 4 | May 13–27 (transplant) | – |
| Eggplant | Feb 18–Mar 4 | May 13–27 (transplant) | – |
| Tomatillo | Mar 4–18 | May 6–20 (transplant) | – |
| Lettuce | Mar 4–18 | Apr 8–29 (transplant) Apr 1–May 13 (sow outdoors) | Aug 9–30 (transplant) Jul 26–Aug 23 (sowing) |
| Spinach | – | Mar 18–Apr 8 (sow outdoors) | Aug 9–30 (sowing) |
| Kale | Mar 4–18 | Apr 1–15 (transplant) Apr 1–15 (sow outdoors) | Jul 12–Aug 9 (transplant) Jun 28–Jul 26 (sowing) |
| Collards | Mar 4–18 | Apr 1–29 (transplant) Apr 1–29 (sow outdoors) | Jul 12–Aug 9 (transplant) Jun 28–Jul 26 (sowing) |
| Broccoli | Feb 18–Mar 4 | Apr 1–15 (transplant) | Jun 28–Jul 26 (transplant) |
| Cabbage | Feb 18–Mar 4 | Apr 1–15 (transplant) | Jun 28–Jul 26 (transplant) |
| Cauliflower | Feb 18–Mar 4 | Apr 15–29 (transplant) | Jun 28–Jul 26 (transplant) |
| Brussels sprouts | Feb 4–18 | Apr 1–15 (transplant) | Jun 14–Jul 5 (transplant) |
| Kohlrabi | Mar 4–18 | Apr 1–15 (transplant) Apr 1–15 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Bok choy / Asian greens | – | Apr 1–15 (sow outdoors) | Aug 9–23 (sowing) |
| Arugula | – | Apr 1–29 (sow outdoors) | Aug 9–Sep 6 (sowing) |
| Mustard greens | – | Apr 1–22 (sow outdoors) | Aug 9–23 (sowing) |
| Swiss chard | Mar 18–Apr 1 | Apr 15–May 6 (transplant) Apr 15–May 13 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Beet | – | Apr 1–29 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Carrot | – | Apr 8–May 6 (sow outdoors) | Jul 12–26 (sowing) |
| Radish | – | Mar 25–May 6 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Turnip | – | Apr 1–22 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Parsnip | – | Apr 8–29 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 4–Apr 1 (sow outdoors) | Jul 12–26 (sowing) |
| Onion (bulbing) | Feb 4–18 | Mar 18–Apr 1 (transplant) | – |
| Green onion / scallion | – | Mar 18–Apr 15 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Leek | Feb 4–18 | Apr 1–15 (transplant) | – |
| Garlic | – | – | Aug 23–Sep 20 (sowing) |
| Shallot | – | Mar 18–Apr 1 (transplant) | Aug 23–Sep 20 (sowing) |
| Potato | – | Apr 1–15 (transplant) | Jun 14–28 (transplant) |
| Sweet potato | – | May 20–Jun 3 (transplant) | – |
| Sweet corn | – | May 6–20 (sow outdoors) | – |
| Bean, bush (snap) | – | May 6–20 (sow outdoors) | – |
| Bean, pole | – | May 6–20 (sow outdoors) | – |
| Lima bean | – | May 13–27 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 20–Jun 10 (sow outdoors) | – |
| Cucumber | Apr 1–8 | May 6–20 (transplant) May 6–20 (sow outdoors) | – |
| Summer squash / zucchini | Apr 1–8 | May 6–20 (transplant) May 6–20 (sow outdoors) | – |
| Winter squash | Apr 1–8 | May 6–20 (transplant) May 6–20 (sow outdoors) | – |
| Pumpkin | – | May 6–20 (sow outdoors) | – |
| Watermelon | Apr 1–8 | May 13–27 (transplant) May 13–27 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 1–8 | May 13–27 (transplant) May 13–27 (sow outdoors) | – |
| Okra | Mar 18–Apr 1 | May 13–27 (transplant) May 13–27 (sow outdoors) | – |
| Celery | Feb 4–18 | May 6–13 (transplant) | – |
| Basil | Mar 18–Apr 1 | May 6–20 (transplant) May 6–20 (sow outdoors) | – |
| Cilantro | – | Apr 15–May 13 (sow outdoors) | Aug 9–23 (sowing) |
| Parsley | Feb 18–Mar 4 | Apr 15–29 (transplant) Apr 8–29 (sow outdoors) | – |
| Dill | – | Apr 29–May 13 (sow outdoors) | Aug 9–23 (sowing) |
| Sunflower | – | Apr 29–May 13 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 1–15 (transplant) | – |
| Rhubarb (crowns) | – | Apr 1–15 (transplant) | – |
| Strawberry (plants) | – | Apr 1–15 (transplant) | Jul 26–Aug 23 (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: St John, WA (NOAA GHCN-Daily ID USC00457267), elevation 1,952 ft, 15.4 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Ritzville 1 SSE, WA | 23 mi | May 7 | Oct 10 |
| Spokane 17 SSW, WA | 23 mi | May 30 | Sep 4 |
| Rosalia, WA | 25 mi | May 7 | Sep 28 |
The average last-frost dates of these stations span 32 days, a rough guide to local variation. See data sources & methods.
Frost questions for 99017
When is the last frost in 99017?
The average (50% chance) last spring freeze of 32°F for ZIP 99017 is April 29. For a more cautious planting date, use May 15, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99017?
The average first fall freeze is October 4. In 1 year in 10 it comes by September 19.
What hardiness zone is 99017?
ZIP 99017 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 99017 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
99032 Sprague 99171 St. John 99125 Endicott 99105 99149 Malden 99004 Cheney 99008 99176
Other ZIP codes in Whitman County
99033 99102 99111 99113 99125 99128 99130 99136 99143 99149 99158 99161 99163 99170 99171 99174 99176 99179 99333 All Whitman County frost dates · Washington frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
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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.