Fall in zone 6bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 97633 (Merrill, 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, Tulelake, CA (7 miles away).
- Average last spring frostJun 650% chance of a 32°F freeze after this date
- Average first fall frostSep 1450% chance of a 32°F freeze by this date
- Growing season (frost-free)97 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 97633 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 March to April.
Fertilizer window
Lawn region: Pacific Northwest (west of the Cascades). Timing only; always follow the product label.
- Perennial ryegrass (cool-season): Early fall: September; Late fall: October–November; Overseeded Bermuda: Light feeding once the winter rye is established, if needed. Avoid: Summer feeding.
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) | May 18 |
| 50% (the "average" last frost) | Jun 6 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 23 |
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) | Aug 30 |
| 50% (the "average" first frost) | Sep 14 |
| 90% (late: most years have frozen by now) | Sep 26 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | n/a | n/a |
| 32°F (freeze) | Jun 6 | Sep 14 |
| 28°F (hard freeze) | May 16 | Sep 27 |
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 97633
Dates count from your average last spring frost (Jun 6) and first fall frost (Sep 14). 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 | Apr 11–25 | Jun 13–27 (transplant) | – |
| Pepper (sweet and hot) | Mar 28–Apr 11 | Jun 20–Jul 4 (transplant) | – |
| Eggplant | Mar 28–Apr 11 | Jun 20–Jul 4 (transplant) | – |
| Tomatillo | Apr 11–25 | Jun 13–27 (transplant) | – |
| Lettuce | Apr 11–25 | May 16–Jun 6 (transplant) May 9–Jun 20 (sow outdoors) | Jul 20–Aug 10 (transplant) Jul 6–Aug 3 (sowing) |
| Spinach | – | Apr 25–May 16 (sow outdoors) | Jul 20–Aug 10 (sowing) |
| Kale | Apr 11–25 | May 9–23 (transplant) May 9–23 (sow outdoors) | Jun 22–Jul 20 (transplant) Jun 8–Jul 6 (sowing) |
| Collards | Apr 11–25 | May 9–Jun 6 (transplant) May 9–Jun 6 (sow outdoors) | Jun 22–Jul 20 (transplant) Jun 8–Jul 6 (sowing) |
| Broccoli | Mar 28–Apr 11 | May 9–23 (transplant) | Jun 8–Jul 6 (transplant) |
| Cabbage | Mar 28–Apr 11 | May 9–23 (transplant) | Jun 8–Jul 6 (transplant) |
| Cauliflower | Mar 28–Apr 11 | May 23–Jun 6 (transplant) | Jun 8–Jul 6 (transplant) |
| Brussels sprouts | Mar 14–28 | May 9–23 (transplant) | May 25–Jun 15 (transplant) |
| Kohlrabi | Apr 11–25 | May 9–23 (transplant) May 9–23 (sow outdoors) | Jul 6–20 (sowing) |
| Bok choy / Asian greens | – | May 9–23 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Arugula | – | May 9–Jun 6 (sow outdoors) | Jul 20–Aug 17 (sowing) |
| Mustard greens | – | May 9–30 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Swiss chard | Apr 25–May 9 | May 23–Jun 13 (transplant) May 23–Jun 20 (sow outdoors) | Jul 6–20 (sowing) |
| Beet | – | May 9–Jun 6 (sow outdoors) | Jul 6–20 (sowing) |
| Carrot | – | May 16–Jun 13 (sow outdoors) | Jun 22–Jul 6 (sowing) |
| Radish | – | May 2–Jun 13 (sow outdoors) | Aug 3–17 (sowing) |
| Turnip | – | May 9–30 (sow outdoors) | Jul 6–20 (sowing) |
| Parsnip | – | May 16–Jun 6 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 11–May 9 (sow outdoors) | Jun 22–Jul 6 (sowing) |
| Onion (bulbing) | Mar 14–28 | Apr 25–May 9 (transplant) | – |
| Green onion / scallion | – | Apr 25–May 23 (sow outdoors) | Jul 6–20 (sowing) |
| Leek | Mar 14–28 | May 9–23 (transplant) | – |
| Garlic | – | – | Aug 3–31 (sowing) |
| Shallot | – | Apr 25–May 9 (transplant) | Aug 3–31 (sowing) |
| Potato | – | May 9–23 (transplant) | May 25–Jun 8 (transplant) |
| Sweet potato | – | Jun 27–Jul 11 (transplant) | – |
| Sweet corn | – | Jun 13–27 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 13–27 (sow outdoors) | – |
| Bean, pole | – | Jun 13–27 (sow outdoors) | – |
| Lima bean | – | Jun 20–Jul 4 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 27–Jul 18 (sow outdoors) | – |
| Cucumber | May 9–16 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Summer squash / zucchini | May 9–16 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Winter squash | May 9–16 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Pumpkin | – | Jun 13–27 (sow outdoors) | – |
| Watermelon | May 9–16 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 9–16 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Okra | Apr 25–May 9 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Celery | Mar 14–28 | Jun 13–20 (transplant) | – |
| Basil | Apr 25–May 9 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Cilantro | – | May 23–Jun 20 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Parsley | Mar 28–Apr 11 | May 23–Jun 6 (transplant) May 16–Jun 6 (sow outdoors) | – |
| Dill | – | Jun 6–20 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Sunflower | – | Jun 6–20 (sow outdoors) | – |
| Asparagus (crowns) | – | May 9–23 (transplant) | – |
| Rhubarb (crowns) | – | May 9–23 (transplant) | – |
| Strawberry (plants) | – | May 9–23 (transplant) | Jul 6–Aug 3 (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: Tulelake, CA (NOAA GHCN-Daily ID USC00049053), elevation 4,038 ft, 6.8 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Klamath Falls Intl AP, OR | 11 mi | Jun 9 | Sep 18 |
| Keno, OR | 18 mi | Jun 5 | Sep 20 |
| Lava Beds Nat Mon, CA | 23 mi | Jun 6 | Sep 28 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 97633
When is the last frost in 97633?
The average (50% chance) last spring freeze of 32°F for ZIP 97633 is June 6. For a more cautious planting date, use June 23, when only 1 year in 10 still sees a later freeze.
When is the first frost in 97633?
The average first fall freeze is September 14. In 1 year in 10 it comes by August 30.
What hardiness zone is 97633?
ZIP 97633 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 97633 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
97632 Malin 97603 Altamont 97634 96134 Newell 97623 Bonanza 97625 96023 Dorris 97627 Keno
Other ZIP codes in Klamath County
97601 97603 97604 97621 97622 97623 97624 97625 97626 97627 97632 97634 97639 97731 97733 97737 All Klamath County frost dates · Oregon frost dates
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- Freeze alerts
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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.