Frost dates for ZIP 99720 (Alatna, 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, Bettles AP, AK (42 miles away).
Station is a bit far
The nearest station with freeze normals is over 40 km away, so dates here may be off by a week or more.
- Average last spring frostMay 2250% chance of a 32°F freeze after this date
- Average first fall frostAug 2450% chance of a 32°F freeze by this date
- Growing season (frost-free)94 daysmedian, 32°F threshold
- USDA hardiness zone1a-60 to -55°F avg. coldest night
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This week in your yard
As of Oct 17, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
32°F Below 50°F
24-hour average · latest 32°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Kanuti Lake (39 mi).
4-inch depth
32°F Below 50°F
24-hour average · latest 32°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Kanuti Lake (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 99720 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 32°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 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 11 |
| 50% (the "average" last frost) | May 22 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 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) | Aug 10 |
| 50% (the "average" first frost) | Aug 24 |
| 90% (late: most years have frozen by now) | Sep 9 |
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 22 | Aug 24 |
| 28°F (hard freeze) | May 13 | Sep 5 |
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 99720
Dates count from your average last spring frost (May 22) and first fall frost (Aug 24). 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 27–Apr 10 | May 29–Jun 12 (transplant) | – |
| Pepper (sweet and hot) | Mar 13–27 | Jun 5–19 (transplant) | – |
| Eggplant | Mar 13–27 | Jun 5–19 (transplant) | – |
| Tomatillo | Mar 27–Apr 10 | May 29–Jun 12 (transplant) | – |
| Lettuce | Mar 27–Apr 10 | May 1–22 (transplant) Apr 24–Jun 5 (sow outdoors) | Jun 29–Jul 20 (transplant) Jun 15–Jul 13 (sowing) |
| Spinach | – | Apr 10–May 1 (sow outdoors) | Jun 29–Jul 20 (sowing) |
| Kale | Mar 27–Apr 10 | Apr 24–May 8 (transplant) Apr 24–May 8 (sow outdoors) | Jun 1–29 (transplant) May 18–Jun 15 (sowing) |
| Collards | Mar 27–Apr 10 | Apr 24–May 22 (transplant) Apr 24–May 22 (sow outdoors) | Jun 1–29 (transplant) |
| Broccoli | Mar 13–27 | Apr 24–May 8 (transplant) | May 18–Jun 15 (transplant) |
| Cabbage | Mar 13–27 | Apr 24–May 8 (transplant) | May 18–Jun 15 (transplant) |
| Cauliflower | Mar 13–27 | May 8–22 (transplant) | – |
| Brussels sprouts | Feb 27–Mar 13 | Apr 24–May 8 (transplant) | – |
| Kohlrabi | Mar 27–Apr 10 | Apr 24–May 8 (transplant) Apr 24–May 8 (sow outdoors) | Jun 15–29 (sowing) |
| Bok choy / Asian greens | – | Apr 24–May 8 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Arugula | – | Apr 24–May 22 (sow outdoors) | Jun 29–Jul 27 (sowing) |
| Mustard greens | – | Apr 24–May 15 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Swiss chard | Apr 10–24 | May 8–29 (transplant) May 8–Jun 5 (sow outdoors) | Jun 15–29 (sowing) |
| Beet | – | Apr 24–May 22 (sow outdoors) | Jun 15–29 (sowing) |
| Carrot | – | May 1–29 (sow outdoors) | Jun 1–15 (sowing) |
| Radish | – | Apr 17–May 29 (sow outdoors) | Jul 13–27 (sowing) |
| Turnip | – | Apr 24–May 15 (sow outdoors) | Jun 15–29 (sowing) |
| Parsnip | – | May 1–22 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 27–Apr 24 (sow outdoors) | Jun 1–15 (sowing) |
| Onion (bulbing) | Feb 27–Mar 13 | Apr 10–24 (transplant) | – |
| Green onion / scallion | – | Apr 10–May 8 (sow outdoors) | Jun 15–29 (sowing) |
| Leek | Feb 27–Mar 13 | Apr 24–May 8 (transplant) | – |
| Garlic | – | – | Jul 13–Aug 10 (sowing) |
| Shallot | – | Apr 10–24 (transplant) | Jul 13–Aug 10 (sowing) |
| Potato | – | Apr 24–May 8 (transplant) | – |
| Sweet potato | – | Jun 12–26 (transplant) | – |
| Sweet corn | – | May 29–Jun 12 (sow outdoors) | – |
| Bean, bush (snap) | – | May 29–Jun 12 (sow outdoors) | – |
| Bean, pole | – | May 29–Jun 12 (sow outdoors) | – |
| Lima bean | – | Jun 5–19 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 12–Jul 3 (sow outdoors) | – |
| Cucumber | Apr 24–May 1 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Summer squash / zucchini | Apr 24–May 1 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Winter squash | Apr 24–May 1 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Pumpkin | – | May 29–Jun 12 (sow outdoors) | – |
| Watermelon | Apr 24–May 1 | Jun 5–19 (transplant) Jun 5–19 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 24–May 1 | Jun 5–19 (transplant) Jun 5–19 (sow outdoors) | – |
| Okra | Apr 10–24 | Jun 5–19 (transplant) Jun 5–19 (sow outdoors) | – |
| Celery | Feb 27–Mar 13 | May 29–Jun 5 (transplant) | – |
| Basil | Apr 10–24 | May 29–Jun 12 (transplant) May 29–Jun 12 (sow outdoors) | – |
| Cilantro | – | May 8–Jun 5 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Parsley | Mar 13–27 | May 8–22 (transplant) May 1–22 (sow outdoors) | – |
| Dill | – | May 22–Jun 5 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Sunflower | – | May 22–Jun 5 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 24–May 8 (transplant) | – |
| Rhubarb (crowns) | – | Apr 24–May 8 (transplant) | – |
| Strawberry (plants) | – | Apr 24–May 8 (transplant) | Jun 15–Jul 13 (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: Bettles AP, AK (NOAA GHCN-Daily ID USW00026533), elevation 642 ft, 42.1 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|
Frost questions for 99720
When is the last frost in 99720?
The average (50% chance) last spring freeze of 32°F for ZIP 99720 is May 22. For a more cautious planting date, use June 5, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99720?
The average first fall freeze is August 24. In 1 year in 10 it comes by August 10.
What hardiness zone is 99720?
ZIP 99720 is in USDA zone 1a (-60 to -55°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 99720 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
99726 Evansville 99745 Hughes 99768 Ruby 99777 Tanana 99701 Wiseman 99767 Rampart 99774 Stevens Village 99721 Anaktuvuk Pass
Other ZIP codes in Yukon-Koyukuk Census Area
99558 99590 99602 99627 99665 99675 99691 99701 99722 99724 99726 99730 99733 99740 99741 99745 99746 99748 99754 99756 99757 99758 99760 99765 All Yukon-Koyukuk Census Area frost dates · Alaska frost dates
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