Frost dates for ZIP 99631 (Moose Pass, 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, Moose Pass 3NW, AK (10 miles away).
- Average last spring frostMay 3150% chance of a 32°F freeze after this date
- Average first fall frostSep 850% chance of a 32°F freeze by this date
- Growing season (frost-free)99 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°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
40°F Below 50°F
24-hour average · latest 42°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Kenai 29 ENE (29 mi).
4-inch depth
40°F Below 50°F
24-hour average · latest 41°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Kenai 29 ENE (29 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 99631 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 40°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 19 |
| 50% (the "average" last frost) | May 31 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 15 |
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 24 |
| 50% (the "average" first frost) | Sep 8 |
| 90% (late: most years have frozen by now) | Sep 25 |
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 8 |
| 28°F (hard freeze) | May 14 | Sep 22 |
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 99631
Dates count from your average last spring frost (May 31) and first fall frost (Sep 8). 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 14–Aug 4 (transplant) Jun 30–Jul 28 (sowing) |
| Spinach | – | Apr 19–May 10 (sow outdoors) | Jul 14–Aug 4 (sowing) |
| Kale | Apr 5–19 | May 3–17 (transplant) May 3–17 (sow outdoors) | Jun 16–Jul 14 (transplant) Jun 2–30 (sowing) |
| Collards | Apr 5–19 | May 3–31 (transplant) May 3–31 (sow outdoors) | Jun 16–Jul 14 (transplant) Jun 2–30 (sowing) |
| Broccoli | Mar 22–Apr 5 | May 3–17 (transplant) | Jun 2–30 (transplant) |
| Cabbage | Mar 22–Apr 5 | May 3–17 (transplant) | Jun 2–30 (transplant) |
| Cauliflower | Mar 22–Apr 5 | May 17–31 (transplant) | Jun 2–30 (transplant) |
| Brussels sprouts | Mar 8–22 | May 3–17 (transplant) | May 19–Jun 9 (transplant) |
| Kohlrabi | Apr 5–19 | May 3–17 (transplant) May 3–17 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Bok choy / Asian greens | – | May 3–17 (sow outdoors) | Jul 14–28 (sowing) |
| Arugula | – | May 3–31 (sow outdoors) | Jul 14–Aug 11 (sowing) |
| Mustard greens | – | May 3–24 (sow outdoors) | Jul 14–28 (sowing) |
| Swiss chard | Apr 19–May 3 | May 17–Jun 7 (transplant) May 17–Jun 14 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Beet | – | May 3–31 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Carrot | – | May 10–Jun 7 (sow outdoors) | Jun 16–30 (sowing) |
| Radish | – | Apr 26–Jun 7 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Turnip | – | May 3–24 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Parsnip | – | May 10–31 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 5–May 3 (sow outdoors) | Jun 16–30 (sowing) |
| Onion (bulbing) | Mar 8–22 | Apr 19–May 3 (transplant) | – |
| Green onion / scallion | – | Apr 19–May 17 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Leek | Mar 8–22 | May 3–17 (transplant) | – |
| Garlic | – | – | Jul 28–Aug 25 (sowing) |
| Shallot | – | Apr 19–May 3 (transplant) | Jul 28–Aug 25 (sowing) |
| Potato | – | May 3–17 (transplant) | May 19–Jun 2 (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 14–28 (sowing) |
| Parsley | Mar 22–Apr 5 | May 17–31 (transplant) May 10–31 (sow outdoors) | – |
| Dill | – | May 31–Jun 14 (sow outdoors) | Jul 14–28 (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 30–Jul 28 (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: Moose Pass 3NW, AK (NOAA GHCN-Daily ID USC00505894), elevation 492 ft, 9.7 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Cooper Landing 5 W, AK | 13 mi | Jun 12 | Sep 1 |
| Cooper Lake Project, AK | 14 mi | May 18 | Sep 27 |
| Seward 19N, AK | 19 mi | May 21 | Sep 26 |
The average last-frost dates of these stations span 25 days, a rough guide to local variation. See data sources & methods.
Frost questions for 99631
When is the last frost in 99631?
The average (50% chance) last spring freeze of 32°F for ZIP 99631 is May 31. For a more cautious planting date, use June 15, when only 1 year in 10 still sees a later freeze.
When is the first frost in 99631?
The average first fall freeze is September 8. In 1 year in 10 it comes by August 24.
What hardiness zone is 99631?
ZIP 99631 is in USDA zone 5a (-20 to -15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 99631 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
99572 Cooper Landing 99605 Hope 99540 Anchorage 99664 Bear Creek 99516 Anchorage 99507 Anchorage 99587 Anchorage 99515 Anchorage
Other ZIP codes in Kenai Peninsula Borough
99556 99568 99572 99603 99605 99610 99611 99635 99639 99663 99664 99669 99672 99682 All Kenai Peninsula Borough frost dates · Alaska frost dates
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