Fall in zone 6bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 97721 (Harney County, OR)
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, Fields, OR (22 miles away).
- Average last spring frostMay 1050% chance of a 32°F freeze after this date
- Average first fall frostOct 750% chance of a 32°F freeze by this date
- Growing season (frost-free)145 daysmedian, 32°F threshold
- USDA hardiness zone6b-5 to 0°F avg. coldest night
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Frost and freeze alerts from the NWS forecast for 97721, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
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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 97721 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 25 |
| 50% (the "average" last frost) | May 10 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 3 |
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 21 |
| 50% (the "average" first frost) | Oct 7 |
| 90% (late: most years have frozen by now) | Oct 21 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jun 4 | Sep 25 |
| 32°F (freeze) | May 10 | Oct 7 |
| 28°F (hard freeze) | Apr 27 | Oct 19 |
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 97721
Dates count from your average last spring frost (May 10) and first fall frost (Oct 7). 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 15–29 | May 17–31 (transplant) | – |
| Pepper (sweet and hot) | Mar 1–15 | May 24–Jun 7 (transplant) | – |
| Eggplant | Mar 1–15 | May 24–Jun 7 (transplant) | – |
| Tomatillo | Mar 15–29 | May 17–31 (transplant) | – |
| Lettuce | Mar 15–29 | Apr 19–May 10 (transplant) Apr 12–May 24 (sow outdoors) | Aug 12–Sep 2 (transplant) Jul 29–Aug 26 (sowing) |
| Spinach | – | Mar 29–Apr 19 (sow outdoors) | Aug 12–Sep 2 (sowing) |
| Kale | Mar 15–29 | Apr 12–26 (transplant) Apr 12–26 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Collards | Mar 15–29 | Apr 12–May 10 (transplant) Apr 12–May 10 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Broccoli | Mar 1–15 | Apr 12–26 (transplant) | Jul 1–29 (transplant) |
| Cabbage | Mar 1–15 | Apr 12–26 (transplant) | Jul 1–29 (transplant) |
| Cauliflower | Mar 1–15 | Apr 26–May 10 (transplant) | Jul 1–29 (transplant) |
| Brussels sprouts | Feb 15–Mar 1 | Apr 12–26 (transplant) | Jun 17–Jul 8 (transplant) |
| Kohlrabi | Mar 15–29 | Apr 12–26 (transplant) Apr 12–26 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Bok choy / Asian greens | – | Apr 12–26 (sow outdoors) | Aug 12–26 (sowing) |
| Arugula | – | Apr 12–May 10 (sow outdoors) | Aug 12–Sep 9 (sowing) |
| Mustard greens | – | Apr 12–May 3 (sow outdoors) | Aug 12–26 (sowing) |
| Swiss chard | Mar 29–Apr 12 | Apr 26–May 17 (transplant) Apr 26–May 24 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Beet | – | Apr 12–May 10 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Carrot | – | Apr 19–May 17 (sow outdoors) | Jul 15–29 (sowing) |
| Radish | – | Apr 5–May 17 (sow outdoors) | Aug 26–Sep 9 (sowing) |
| Turnip | – | Apr 12–May 3 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Parsnip | – | Apr 19–May 10 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 15–Apr 12 (sow outdoors) | Jul 15–29 (sowing) |
| Onion (bulbing) | Feb 15–Mar 1 | Mar 29–Apr 12 (transplant) | – |
| Green onion / scallion | – | Mar 29–Apr 26 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Leek | Feb 15–Mar 1 | Apr 12–26 (transplant) | – |
| Garlic | – | – | Aug 26–Sep 23 (sowing) |
| Shallot | – | Mar 29–Apr 12 (transplant) | Aug 26–Sep 23 (sowing) |
| Potato | – | Apr 12–26 (transplant) | Jun 17–Jul 1 (transplant) |
| Sweet potato | – | May 31–Jun 14 (transplant) | – |
| Sweet corn | – | May 17–31 (sow outdoors) | – |
| Bean, bush (snap) | – | May 17–31 (sow outdoors) | – |
| Bean, pole | – | May 17–31 (sow outdoors) | – |
| Lima bean | – | May 24–Jun 7 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 31–Jun 21 (sow outdoors) | – |
| Cucumber | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Summer squash / zucchini | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Winter squash | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Pumpkin | – | May 17–31 (sow outdoors) | – |
| Watermelon | Apr 12–19 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 12–19 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Okra | Mar 29–Apr 12 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Celery | Feb 15–Mar 1 | May 17–24 (transplant) | – |
| Basil | Mar 29–Apr 12 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Cilantro | – | Apr 26–May 24 (sow outdoors) | Aug 12–26 (sowing) |
| Parsley | Mar 1–15 | Apr 26–May 10 (transplant) Apr 19–May 10 (sow outdoors) | – |
| Dill | – | May 10–24 (sow outdoors) | Aug 12–26 (sowing) |
| Sunflower | – | May 10–24 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 12–26 (transplant) | – |
| Rhubarb (crowns) | – | Apr 12–26 (transplant) | – |
| Strawberry (plants) | – | Apr 12–26 (transplant) | Jul 29–Aug 26 (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: Fields, OR (NOAA GHCN-Daily ID USC00352876), elevation 4,227 ft, 21.6 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Rome St AP, OR | 30 mi | May 26 | Sep 21 |
| Mc Dermitt 26 N, OR | 31 mi | Jun 4 | Sep 26 |
| Denio, NV | 38 mi | May 30 | Sep 18 |
The average last-frost dates of these stations span 25 days, a rough guide to local variation. See data sources & methods.
Frost questions for 97721
When is the last frost in 97721?
The average (50% chance) last spring freeze of 32°F for ZIP 97721 is May 10. For a more cautious planting date, use June 3, when only 1 year in 10 still sees a later freeze.
When is the first frost in 97721?
The average first fall freeze is October 7. In 1 year in 10 it comes by September 21.
What hardiness zone is 97721?
ZIP 97721 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 97721 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
97736 97710 97722 89421 89404 Denio 97910 Jordan Valley 97902 97732 Crane
Other ZIP codes in Harney County
97710 97720 97722 97732 97736 97738 97758 97904 All Harney County frost dates · Oregon frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- 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.