Fall in zone 7aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 83520 (Clearwater County, ID)
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, Dworshak Fish Hatchery, ID (3 miles away).
- Average last spring frostApr 2050% chance of a 32°F freeze after this date
- Average first fall frostOct 2050% chance of a 32°F freeze by this date
- Growing season (frost-free)182 daysmedian, 32°F threshold
- USDA hardiness zone7a0 to 5°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
54°F 50–55°F
24-hour average · latest 49°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Cook Farm Field D (39 mi).
4-inch depth
55°F 50–55°F
24-hour average · latest 53°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Cook Farm Field D (39 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 83520 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 55°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.
Your average first frost is Oct 20: 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) | Apr 1 |
| 50% (the "average" last frost) | Apr 20 |
| 10% (cautious: only 1 year in 10 freezes later) | May 5 |
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 30 |
| 50% (the "average" first frost) | Oct 20 |
| 90% (late: most years have frozen by now) | Nov 7 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 5 | Oct 6 |
| 32°F (freeze) | Apr 20 | Oct 20 |
| 28°F (hard freeze) | Mar 28 | Nov 2 |
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 83520
Dates count from your average last spring frost (Apr 20) and first fall frost (Oct 20). 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 23–Mar 9 | Apr 27–May 11 (transplant) | – |
| Pepper (sweet and hot) | Feb 9–23 | May 4–18 (transplant) | – |
| Eggplant | Feb 9–23 | May 4–18 (transplant) | – |
| Tomatillo | Feb 23–Mar 9 | Apr 27–May 11 (transplant) | – |
| Lettuce | Feb 23–Mar 9 | Mar 30–Apr 20 (transplant) Mar 23–May 4 (sow outdoors) | Aug 25–Sep 15 (transplant) Aug 11–Sep 8 (sowing) |
| Spinach | – | Mar 9–30 (sow outdoors) | Aug 25–Sep 15 (sowing) |
| Kale | Feb 23–Mar 9 | Mar 23–Apr 6 (transplant) Mar 23–Apr 6 (sow outdoors) | Jul 28–Aug 25 (transplant) Jul 14–Aug 11 (sowing) |
| Collards | Feb 23–Mar 9 | Mar 23–Apr 20 (transplant) Mar 23–Apr 20 (sow outdoors) | Jul 28–Aug 25 (transplant) Jul 14–Aug 11 (sowing) |
| Broccoli | Feb 9–23 | Mar 23–Apr 6 (transplant) | Jul 14–Aug 11 (transplant) |
| Cabbage | Feb 9–23 | Mar 23–Apr 6 (transplant) | Jul 14–Aug 11 (transplant) |
| Cauliflower | Feb 9–23 | Apr 6–20 (transplant) | Jul 14–Aug 11 (transplant) |
| Brussels sprouts | Jan 26–Feb 9 | Mar 23–Apr 6 (transplant) | Jun 30–Jul 21 (transplant) |
| Kohlrabi | Feb 23–Mar 9 | Mar 23–Apr 6 (transplant) Mar 23–Apr 6 (sow outdoors) | Aug 11–25 (sowing) |
| Bok choy / Asian greens | – | Mar 23–Apr 6 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Arugula | – | Mar 23–Apr 20 (sow outdoors) | Aug 25–Sep 22 (sowing) |
| Mustard greens | – | Mar 23–Apr 13 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Swiss chard | Mar 9–23 | Apr 6–27 (transplant) Apr 6–May 4 (sow outdoors) | Aug 11–25 (sowing) |
| Beet | – | Mar 23–Apr 20 (sow outdoors) | Aug 11–25 (sowing) |
| Carrot | – | Mar 30–Apr 27 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Radish | – | Mar 16–Apr 27 (sow outdoors) | Sep 8–22 (sowing) |
| Turnip | – | Mar 23–Apr 13 (sow outdoors) | Aug 11–25 (sowing) |
| Parsnip | – | Mar 30–Apr 20 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 23–Mar 23 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Onion (bulbing) | Jan 26–Feb 9 | Mar 9–23 (transplant) | – |
| Green onion / scallion | – | Mar 9–Apr 6 (sow outdoors) | Aug 11–25 (sowing) |
| Leek | Jan 26–Feb 9 | Mar 23–Apr 6 (transplant) | – |
| Garlic | – | – | Sep 8–Oct 6 (sowing) |
| Shallot | – | Mar 9–23 (transplant) | Sep 8–Oct 6 (sowing) |
| Potato | – | Mar 23–Apr 6 (transplant) | Jun 30–Jul 14 (transplant) |
| Sweet potato | – | May 11–25 (transplant) | – |
| Sweet corn | – | Apr 27–May 11 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 27–May 11 (sow outdoors) | – |
| Bean, pole | – | Apr 27–May 11 (sow outdoors) | – |
| Lima bean | – | May 4–18 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 11–Jun 1 (sow outdoors) | – |
| Cucumber | Mar 23–30 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | – |
| Summer squash / zucchini | Mar 23–30 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | – |
| Winter squash | Mar 23–30 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | – |
| Pumpkin | – | Apr 27–May 11 (sow outdoors) | – |
| Watermelon | Mar 23–30 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 23–30 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Okra | Mar 9–23 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Celery | Jan 26–Feb 9 | Apr 27–May 4 (transplant) | – |
| Basil | Mar 9–23 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | – |
| Cilantro | – | Apr 6–May 4 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Parsley | Feb 9–23 | Apr 6–20 (transplant) Mar 30–Apr 20 (sow outdoors) | – |
| Dill | – | Apr 20–May 4 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Sunflower | – | Apr 20–May 4 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 23–Apr 6 (transplant) | – |
| Rhubarb (crowns) | – | Mar 23–Apr 6 (transplant) | – |
| Strawberry (plants) | – | Mar 23–Apr 6 (transplant) | Aug 11–Sep 8 (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: Dworshak Fish Hatchery, ID (NOAA GHCN-Daily ID USC00102845), elevation 995 ft, 2.9 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Elk Rvr, ID | 18 mi | May 16 | Sep 23 |
| Nezperce, ID | 22 mi | May 24 | Sep 20 |
| Pierce, ID | 25 mi | Jun 3 | Sep 7 |
The average last-frost dates of these stations span 45 days, a rough guide to local variation. See data sources & methods.
Frost questions for 83520
When is the last frost in 83520?
The average (50% chance) last spring freeze of 32°F for ZIP 83520 is April 20. For a more cautious planting date, use May 5, when only 1 year in 10 still sees a later freeze.
When is the first frost in 83520?
The average first fall freeze is October 20. In 1 year in 10 it comes by September 30.
What hardiness zone is 83520?
ZIP 83520 is in USDA zone 7a (0 to 5°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 83520 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
83541 83544 Orofino 83545 Peck 83537 Kendrick 83548 Reubens 83827 Elk River 83543 Nezperce 83535 Juliaetta
Other ZIP codes in Clearwater County
83544 83546 83553 83827 All Clearwater County frost dates · Idaho frost dates
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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.