Fall in zone 4bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 99635 (Tyonek, 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, Big River Lakes, AK (30 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 750% 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)151 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 99635 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) | Apr 21 |
| 50% (the "average" last frost) | May 7 |
| 10% (cautious: only 1 year in 10 freezes later) | May 25 |
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 20 |
| 50% (the "average" first frost) | Oct 7 |
| 90% (late: most years have frozen by now) | Oct 22 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 22 | Sep 26 |
| 32°F (freeze) | May 7 | Oct 7 |
| 28°F (hard freeze) | Apr 23 | 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 99635
Dates count from your average last spring frost (May 7) 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 12–26 | May 14–28 (transplant) | – |
| Pepper (sweet and hot) | Feb 26–Mar 12 | May 21–Jun 4 (transplant) | – |
| Eggplant | Feb 26–Mar 12 | May 21–Jun 4 (transplant) | – |
| Tomatillo | Mar 12–26 | May 14–28 (transplant) | – |
| Lettuce | Mar 12–26 | Apr 16–May 7 (transplant) Apr 9–May 21 (sow outdoors) | Aug 12–Sep 2 (transplant) Jul 29–Aug 26 (sowing) |
| Spinach | – | Mar 26–Apr 16 (sow outdoors) | Aug 12–Sep 2 (sowing) |
| Kale | Mar 12–26 | Apr 9–23 (transplant) Apr 9–23 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Collards | Mar 12–26 | Apr 9–May 7 (transplant) Apr 9–May 7 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Broccoli | Feb 26–Mar 12 | Apr 9–23 (transplant) | Jul 1–29 (transplant) |
| Cabbage | Feb 26–Mar 12 | Apr 9–23 (transplant) | Jul 1–29 (transplant) |
| Cauliflower | Feb 26–Mar 12 | Apr 23–May 7 (transplant) | Jul 1–29 (transplant) |
| Brussels sprouts | Feb 12–26 | Apr 9–23 (transplant) | Jun 17–Jul 8 (transplant) |
| Kohlrabi | Mar 12–26 | Apr 9–23 (transplant) Apr 9–23 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Bok choy / Asian greens | – | Apr 9–23 (sow outdoors) | Aug 12–26 (sowing) |
| Arugula | – | Apr 9–May 7 (sow outdoors) | Aug 12–Sep 9 (sowing) |
| Mustard greens | – | Apr 9–30 (sow outdoors) | Aug 12–26 (sowing) |
| Swiss chard | Mar 26–Apr 9 | Apr 23–May 14 (transplant) Apr 23–May 21 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Beet | – | Apr 9–May 7 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Carrot | – | Apr 16–May 14 (sow outdoors) | Jul 15–29 (sowing) |
| Radish | – | Apr 2–May 14 (sow outdoors) | Aug 26–Sep 9 (sowing) |
| Turnip | – | Apr 9–30 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Parsnip | – | Apr 16–May 7 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 12–Apr 9 (sow outdoors) | Jul 15–29 (sowing) |
| Onion (bulbing) | Feb 12–26 | Mar 26–Apr 9 (transplant) | – |
| Green onion / scallion | – | Mar 26–Apr 23 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Leek | Feb 12–26 | Apr 9–23 (transplant) | – |
| Garlic | – | – | Aug 26–Sep 23 (sowing) |
| Shallot | – | Mar 26–Apr 9 (transplant) | Aug 26–Sep 23 (sowing) |
| Potato | – | Apr 9–23 (transplant) | Jun 17–Jul 1 (transplant) |
| Sweet potato | – | May 28–Jun 11 (transplant) | – |
| Sweet corn | – | May 14–28 (sow outdoors) | – |
| Bean, bush (snap) | – | May 14–28 (sow outdoors) | – |
| Bean, pole | – | May 14–28 (sow outdoors) | – |
| Lima bean | – | May 21–Jun 4 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 28–Jun 18 (sow outdoors) | – |
| Cucumber | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Summer squash / zucchini | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Winter squash | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Pumpkin | – | May 14–28 (sow outdoors) | – |
| Watermelon | Apr 9–16 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 9–16 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Okra | Mar 26–Apr 9 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Celery | Feb 12–26 | May 14–21 (transplant) | – |
| Basil | Mar 26–Apr 9 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Cilantro | – | Apr 23–May 21 (sow outdoors) | Aug 12–26 (sowing) |
| Parsley | Feb 26–Mar 12 | Apr 23–May 7 (transplant) Apr 16–May 7 (sow outdoors) | – |
| Dill | – | May 7–21 (sow outdoors) | Aug 12–26 (sowing) |
| Sunflower | – | May 7–21 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 9–23 (transplant) | – |
| Rhubarb (crowns) | – | Apr 9–23 (transplant) | – |
| Strawberry (plants) | – | Apr 9–23 (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: Big River Lakes, AK (NOAA GHCN-Daily ID USC00500788), elevation 60 ft, 29.5 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|
Frost questions for 99635
When is the last frost in 99635?
The average (50% chance) last spring freeze of 32°F for ZIP 99635 is May 7. For a more cautious planting date, use May 25, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99635?
The average first fall freeze is October 7. In 1 year in 10 it comes by September 20.
What hardiness zone is 99635?
ZIP 99635 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 99635 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
99667 Skwentna 99682 Beluga 99653 Port Alsworth 99611 Nikiski 99557 Lime Village 99610 Cohoe 99672 Sterling 99669 Kalifornsky
Other ZIP codes in Kenai Peninsula Borough
99556 99568 99572 99603 99605 99610 99611 99631 99639 99663 99664 99669 99672 99682 All Kenai Peninsula Borough frost dates · Alaska 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.