Fall in zone 4bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 99566 (McCarthy, AK)
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, Silver Lake, AK (55 miles away).
Use with caution
The nearest station is far away or at a very different elevation, so local dates may differ a lot.
- Average last spring frostMay 3150% chance of a 32°F freeze after this date
- Average first fall frostSep 350% chance of a 32°F freeze by this date
- Growing season (frost-free)95 daysmedian, 32°F threshold
- USDA hardiness zone4b-25 to -20°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 99566 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 early May.
Fertilizer window
Lawn region: North (cool-season). 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) | May 20 |
| 50% (the "average" last frost) | May 31 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 10 |
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 20 |
| 50% (the "average" first frost) | Sep 3 |
| 90% (late: most years have frozen by now) | Sep 17 |
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) | May 31 | Sep 3 |
| 28°F (hard freeze) | May 16 | Sep 17 |
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 99566
Dates count from your average last spring frost (May 31) and first fall frost (Sep 3). 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 5–19 | Jun 7–21 (transplant) | – |
| Pepper (sweet and hot) | Mar 22–Apr 5 | Jun 14–28 (transplant) | – |
| Eggplant | Mar 22–Apr 5 | Jun 14–28 (transplant) | – |
| Tomatillo | Apr 5–19 | Jun 7–21 (transplant) | – |
| Lettuce | Apr 5–19 | May 10–31 (transplant) May 3–Jun 14 (sow outdoors) | Jul 9–30 (transplant) Jun 25–Jul 23 (sowing) |
| Spinach | – | Apr 19–May 10 (sow outdoors) | Jul 9–30 (sowing) |
| Kale | Apr 5–19 | May 3–17 (transplant) May 3–17 (sow outdoors) | Jun 11–Jul 9 (transplant) May 28–Jun 25 (sowing) |
| Collards | Apr 5–19 | May 3–31 (transplant) May 3–31 (sow outdoors) | Jun 11–Jul 9 (transplant) |
| Broccoli | Mar 22–Apr 5 | May 3–17 (transplant) | May 28–Jun 25 (transplant) |
| Cabbage | Mar 22–Apr 5 | May 3–17 (transplant) | May 28–Jun 25 (transplant) |
| Cauliflower | Mar 22–Apr 5 | May 17–31 (transplant) | – |
| Brussels sprouts | Mar 8–22 | May 3–17 (transplant) | – |
| Kohlrabi | Apr 5–19 | May 3–17 (transplant) May 3–17 (sow outdoors) | Jun 25–Jul 9 (sowing) |
| Bok choy / Asian greens | – | May 3–17 (sow outdoors) | Jul 9–23 (sowing) |
| Arugula | – | May 3–31 (sow outdoors) | Jul 9–Aug 6 (sowing) |
| Mustard greens | – | May 3–24 (sow outdoors) | Jul 9–23 (sowing) |
| Swiss chard | Apr 19–May 3 | May 17–Jun 7 (transplant) May 17–Jun 14 (sow outdoors) | Jun 25–Jul 9 (sowing) |
| Beet | – | May 3–31 (sow outdoors) | Jun 25–Jul 9 (sowing) |
| Carrot | – | May 10–Jun 7 (sow outdoors) | Jun 11–25 (sowing) |
| Radish | – | Apr 26–Jun 7 (sow outdoors) | Jul 23–Aug 6 (sowing) |
| Turnip | – | May 3–24 (sow outdoors) | Jun 25–Jul 9 (sowing) |
| Parsnip | – | May 10–31 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 5–May 3 (sow outdoors) | Jun 11–25 (sowing) |
| Onion (bulbing) | Mar 8–22 | Apr 19–May 3 (transplant) | – |
| Green onion / scallion | – | Apr 19–May 17 (sow outdoors) | Jun 25–Jul 9 (sowing) |
| Leek | Mar 8–22 | May 3–17 (transplant) | – |
| Garlic | – | – | Jul 23–Aug 20 (sowing) |
| Shallot | – | Apr 19–May 3 (transplant) | Jul 23–Aug 20 (sowing) |
| Potato | – | May 3–17 (transplant) | – |
| Sweet potato | – | Jun 21–Jul 5 (transplant) | – |
| Sweet corn | – | Jun 7–21 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 7–21 (sow outdoors) | – |
| Bean, pole | – | Jun 7–21 (sow outdoors) | – |
| Lima bean | – | Jun 14–28 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 21–Jul 12 (sow outdoors) | – |
| Cucumber | May 3–10 | Jun 7–21 (transplant) Jun 7–21 (sow outdoors) | – |
| Summer squash / zucchini | May 3–10 | Jun 7–21 (transplant) Jun 7–21 (sow outdoors) | – |
| Winter squash | May 3–10 | Jun 7–21 (transplant) Jun 7–21 (sow outdoors) | – |
| Pumpkin | – | Jun 7–21 (sow outdoors) | – |
| Watermelon | May 3–10 | Jun 14–28 (transplant) Jun 14–28 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 3–10 | Jun 14–28 (transplant) Jun 14–28 (sow outdoors) | – |
| Okra | Apr 19–May 3 | Jun 14–28 (transplant) Jun 14–28 (sow outdoors) | – |
| Celery | Mar 8–22 | Jun 7–14 (transplant) | – |
| Basil | Apr 19–May 3 | Jun 7–21 (transplant) Jun 7–21 (sow outdoors) | – |
| Cilantro | – | May 17–Jun 14 (sow outdoors) | Jul 9–23 (sowing) |
| Parsley | Mar 22–Apr 5 | May 17–31 (transplant) May 10–31 (sow outdoors) | – |
| Dill | – | May 31–Jun 14 (sow outdoors) | Jul 9–23 (sowing) |
| Sunflower | – | May 31–Jun 14 (sow outdoors) | – |
| Asparagus (crowns) | – | May 3–17 (transplant) | – |
| Rhubarb (crowns) | – | May 3–17 (transplant) | – |
| Strawberry (plants) | – | May 3–17 (transplant) | Jun 25–Jul 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: Silver Lake, AK (NOAA GHCN-Daily ID USC00508470), elevation 1,200 ft, 55.2 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Nabesna, AK | 79 mi | Jun 4 | Sep 1 |
| Port Alcan, AK | 107 mi | May 28 | Aug 29 |
| Northway AP, AK | 119 mi | May 26 | Sep 1 |
The average last-frost dates of these stations span 9 days, a rough guide to local variation. See data sources & methods.
Frost questions for 99566
When is the last frost in 99566?
The average (50% chance) last spring freeze of 32°F for ZIP 99566 is May 31. For a more cautious planting date, use June 10, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99566?
The average first fall freeze is September 3. In 1 year in 10 it comes by August 20.
What hardiness zone is 99566?
ZIP 99566 is in USDA zone 4b (-25 to -20°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 99566 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
99764 Northway 99573 Kenny Lake 99586 Chistochina 99686 Valdez 99677 Tatitlek 99776 Tanacross 99689 Yakutat 99588 Mendeltna
Other ZIP codes in Copper River Census Area
99573 99586 99588 All Copper River Census Area frost dates · Alaska 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.