Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 99624 — Larsen Bay, AK

ZIP code 99624 (Larsen Bay, Kodiak Island County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is May 5 and the first fall frost October 3.

Where ZIP 99624 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostMay 5
First frostOct 3
2012 zone6b

Was 6b on the 2012 map — a full zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Larsen Bay, AK…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Larsen Bay, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 5median — 50% chance of a later frost
Safe for tender plantsMay 21only 10% chance of frost after
First fall frostOctober 3median — 10% chance by Sep 22
Growing season151 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 17.

From the NOAA station Kodiak Airport, AK — 53 miles away, elevation 79 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 99624

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 24 – Apr 7
SpinachSow outdoors · Mar 24 – Apr 14
Broccoli, cabbageStart indoors · Feb 24 – Mar 10
Broccoli, cabbageTransplant · Apr 14 – Apr 28
Onion setsPlant outdoors · Apr 7 – Apr 21
PotatoesPlant outdoors · Apr 14 – Apr 28
LettuceSow outdoors · Apr 7 – Apr 21
Carrots, beetsSow outdoors · Apr 14 – Apr 28
TomatoesStart indoors · Mar 10 – Mar 24
TomatoesTransplant · May 12 – May 26
Peppers, eggplantStart indoors · Feb 24 – Mar 10
Peppers, eggplantTransplant · May 19 – Jun 2
BeansSow outdoors · May 12 – May 26
Sweet cornSow outdoors · May 12 – May 26
Cucumbers, squashSow outdoors · May 12 – May 26
Fall lettuce, spinachSow outdoors · Aug 8 – Aug 22
GarlicPlant cloves · Sep 19 – Oct 24
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 5) and first fall frost (Oct 3) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

Native plants for zone 7b in Alaska

289 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. Each links to its USDA PLANTS profile.

Trees 16

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack spruce65 ft · blooms late spring · low shade tolerance · to −79 °Flodgepole pine99 ft · blooms mid summer · high shade tolerance · to −70 °Fmountain hemlock125 ft · blooms early summer · low shade tolerance · to −18 °FPacific silver fir165 ft · blooms late spring · low shade tolerance · to −28 °F

Shrubs 50

alpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FBarclay's willow15 ft · high shade tolerance · to −43 °Fblack crowberry1 ft · blooms mid summer · high shade tolerance · to −43 °Fblack hawthorn15 ft · blooms mid spring · medium shade tolerance · to −47 °Fbog blueberry2 ft · blooms early summer · medium shade tolerance · to −38 °F

Wildflowers & perennials 125

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine aster0.3 ft · blooms early summer · medium shade tolerance · to −28 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °F

Grasses 89

Alaska brome5 ft · blooms late spring · low shade tolerance · to −18 °FAlaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Farctic bluegrass2 ft · high shade tolerance · to −62 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Larsen Bay, AK.

Soil in Larsen Bay, AK

The soil mapped at the center of ZIP 99624 is Akalura — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
pH4.4strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter75%high
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Akalura-Ayakulik-Koniag complex, 20 to 55 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 99624; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Larsen Bay, AK

Summer high63 °Faverage high, August
Winter low26 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights133nights a year at 32 °F or less
Growing degree days551base 50 °F — the season’s usable heat
Longest day18 h 02 mindaylight on June 21
Shortest day6 h 35 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation78.3 inper year, rain and melted snow
Snowfall70 inper year; 47 days with snow on the ground

Average high and low, by month

20°30°40°50°60°70°32 °FJanuary: average high 36 °F, low 26 °F 36°26° JanFebruary: average high 38 °F, low 27 °F 38°27° FebMarch: average high 39 °F, low 28 °F 39°28° MarApril: average high 45 °F, low 34 °F 45°34° AprMay: average high 52 °F, low 40 °F 52°40° MayJune: average high 57 °F, low 46 °F 57°46° JunJuly: average high 62 °F, low 51 °F 62°51° JulAugust: average high 63 °F, low 50 °F 63°50° AugSeptember: average high 57 °F, low 44 °F 57°44° SepOctober: average high 48 °F, low 36 °F 48°36° OctNovember: average high 41 °F, low 30 °F 41°30° NovDecember: average high 37 °F, low 27 °F 37°27° Dec

Precipitation by month inches · ❄ = snowfall

0″2″4″6″8″January: 8.35 in precipitation, 14.5 in snowfall 8.3❄15 JanFebruary: 6.31 in precipitation, 14.4 in snowfall 6.3❄14 FebMarch: 4.82 in precipitation, 12.3 in snowfall 4.8❄12 MarApril: 6.14 in precipitation, 6.2 in snowfall 6.1❄6 AprMay: 5.85 in precipitation, 0.5 in snowfall 5.8❄1 MayJune: 5.17 in precipitation 5.2 JunJuly: 4.51 in precipitation 4.5 JulAugust: 4.90 in precipitation 4.9 AugSeptember: 7.55 in precipitation 7.5 SepOctober: 8.85 in precipitation, 0.7 in snowfall 8.8❄1 OctNovember: 7.06 in precipitation, 6.1 in snowfall 7.1❄6 NovDecember: 8.81 in precipitation, 15.6 in snowfall 8.8❄16 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Kodiak Airport, AK (53 mi away); precipitation: Kodiak Airport, AK (53 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 7 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

996087a
Karluk, AK · 20 mi
996157a
Kodiak, AK · 22 mi
996437b
Old Harbor, AK · 27 mi
995507a
Port Lions, AK · 45 mi
996197b
Kodiak, AK · 57 mi
996977b
Kodiak, AK · 57 mi
996447b
Ouzinkie, AK · 62 mi

Alaska planting zones →

Questions about 99624

What planting zone is ZIP code 99624?

ZIP code 99624 (Larsen Bay, AK) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Larsen Bay, AK?

The median last spring frost (32 °F) near 99624 is May 5; after May 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Kodiak Airport station.

When is the first frost in Larsen Bay, AK?

The median first fall frost near 99624 is October 3, giving a median frost-free growing season of 151 days.

When should I plant tomatoes in 99624?

Start tomato seeds indoors around Mar 10 – Mar 24 and set transplants outside around May 12 – May 26, one to three weeks after the median last frost.

How much rain and snow does 99624 get?

About 78.3 inches of precipitation a year and 70 inches of snowfall (NOAA 1991–2020 normals, Kodiak Airport station).

How hot do summers get in Larsen Bay, AK?

The average high peaks at 63 °F in August, with about 0 days a year at 90 °F or more.

What kind of soil does 99624 have?

The USDA soil survey maps Akalura at the center of ZIP 99624: moderately decomposed plant material, well drained, pH about 4.4 (strongly acidic).

What kind of onions grow in Larsen Bay, AK?

Long-day onions: the longest day near 99624 is 18 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99624 change?

Yes. The 2012 USDA map put 99624 in zone 6b; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.