Fall in zone 7bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 99363 (Wallula, 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, Ice Harbor Dam, WA (14 miles away).
- Average last spring frostApr 750% 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)199 daysmedian, 32°F threshold
- USDA hardiness zone7b5 to 10°F avg. coldest night
Get The Dial for 99363 (Wallula)
Frost and freeze alerts from the NWS forecast for 99363, 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
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 99363 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.
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) | Mar 20 |
| 50% (the "average" last frost) | Apr 7 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 30 |
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 6 |
| 50% (the "average" first frost) | Oct 22 |
| 90% (late: most years have frozen by now) | Nov 9 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 25 | Oct 10 |
| 32°F (freeze) | Apr 7 | Oct 22 |
| 28°F (hard freeze) | Mar 18 | Nov 4 |
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 99363
Dates count from your average last spring frost (Apr 7) 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 | Feb 10–24 | Apr 14–28 (transplant) | – |
| Pepper (sweet and hot) | Jan 27–Feb 10 | Apr 21–May 5 (transplant) | – |
| Eggplant | Jan 27–Feb 10 | Apr 21–May 5 (transplant) | – |
| Tomatillo | Feb 10–24 | Apr 14–28 (transplant) | – |
| Lettuce | Feb 10–24 | Mar 17–Apr 7 (transplant) Mar 10–Apr 21 (sow outdoors) | Aug 27–Sep 17 (transplant) Aug 13–Sep 10 (sowing) |
| Spinach | – | Feb 24–Mar 17 (sow outdoors) | Aug 27–Sep 17 (sowing) |
| Kale | Feb 10–24 | Mar 10–24 (transplant) Mar 10–24 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Collards | Feb 10–24 | Mar 10–Apr 7 (transplant) Mar 10–Apr 7 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Broccoli | Jan 27–Feb 10 | Mar 10–24 (transplant) | Jul 16–Aug 13 (transplant) |
| Cabbage | Jan 27–Feb 10 | Mar 10–24 (transplant) | Jul 16–Aug 13 (transplant) |
| Cauliflower | Jan 27–Feb 10 | Mar 24–Apr 7 (transplant) | Jul 16–Aug 13 (transplant) |
| Brussels sprouts | Jan 13–27 | Mar 10–24 (transplant) | Jul 2–23 (transplant) |
| Kohlrabi | Feb 10–24 | Mar 10–24 (transplant) Mar 10–24 (sow outdoors) | Aug 13–27 (sowing) |
| Bok choy / Asian greens | – | Mar 10–24 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Arugula | – | Mar 10–Apr 7 (sow outdoors) | Aug 27–Sep 24 (sowing) |
| Mustard greens | – | Mar 10–31 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Swiss chard | Feb 24–Mar 10 | Mar 24–Apr 14 (transplant) Mar 24–Apr 21 (sow outdoors) | Aug 13–27 (sowing) |
| Beet | – | Mar 10–Apr 7 (sow outdoors) | Aug 13–27 (sowing) |
| Carrot | – | Mar 17–Apr 14 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Radish | – | Mar 3–Apr 14 (sow outdoors) | Sep 10–24 (sowing) |
| Turnip | – | Mar 10–31 (sow outdoors) | Aug 13–27 (sowing) |
| Parsnip | – | Mar 17–Apr 7 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 10–Mar 10 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Onion (bulbing) | Jan 13–27 | Feb 24–Mar 10 (transplant) | – |
| Green onion / scallion | – | Feb 24–Mar 24 (sow outdoors) | Aug 13–27 (sowing) |
| Leek | Jan 13–27 | Mar 10–24 (transplant) | – |
| Garlic | – | – | Sep 10–Oct 8 (sowing) |
| Shallot | – | Feb 24–Mar 10 (transplant) | Sep 10–Oct 8 (sowing) |
| Potato | – | Mar 10–24 (transplant) | Jul 2–16 (transplant) |
| Sweet potato | – | Apr 28–May 12 (transplant) | – |
| Sweet corn | – | Apr 14–28 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 14–28 (sow outdoors) | – |
| Bean, pole | – | Apr 14–28 (sow outdoors) | – |
| Lima bean | – | Apr 21–May 5 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 28–May 19 (sow outdoors) | – |
| Cucumber | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Summer squash / zucchini | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Winter squash | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Pumpkin | – | Apr 14–28 (sow outdoors) | – |
| Watermelon | Mar 10–17 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 10–17 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Okra | Feb 24–Mar 10 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Celery | Jan 13–27 | Apr 14–21 (transplant) | – |
| Basil | Feb 24–Mar 10 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Cilantro | – | Mar 24–Apr 21 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Parsley | Jan 27–Feb 10 | Mar 24–Apr 7 (transplant) Mar 17–Apr 7 (sow outdoors) | – |
| Dill | – | Apr 7–21 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Sunflower | – | Apr 7–21 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 10–24 (transplant) | – |
| Rhubarb (crowns) | – | Mar 10–24 (transplant) | – |
| Strawberry (plants) | – | Mar 10–24 (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: Ice Harbor Dam, WA (NOAA GHCN-Daily ID USC00453883), elevation 368 ft, 13.7 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Kennewick, WA | 15 mi | Mar 28 | Oct 30 |
| Pasco Tri Cities AP, WA | 19 mi | Apr 27 | Oct 11 |
| Whitman Mission, WA | 20 mi | May 2 | Oct 1 |
The average last-frost dates of these stations span 36 days, a rough guide to local variation. See data sources & methods.
Frost questions for 99363
When is the last frost in 99363?
The average (50% chance) last spring freeze of 32°F for ZIP 99363 is April 7. For a more cautious planting date, use April 30, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99363?
The average first fall freeze is October 22. In 1 year in 10 it comes by October 6.
What hardiness zone is 99363?
ZIP 99363 is in USDA zone 7b (5 to 10°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 99363 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
99323 Burbank 99337 Finley 99360 Touchet 97835 Helix 99336 Kennewick 99346 97875 Stanfield 99338 Kennewick
Other ZIP codes in Walla Walla County
99323 99324 99329 99348 99360 99361 99362 All Walla Walla 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.