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

Planting zone for 99571 — Cold Bay, AK

ZIP code 99571 (Cold Bay, Aleutians East County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 25 and the first fall frost October 4.

Where ZIP 99571 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostMay 25
First frostOct 4
2012 zone7a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cold 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 Cold Bay, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 25median — 50% chance of a later frost
Safe for tender plantsJune 10only 10% chance of frost after
First fall frostOctober 4median — 10% chance by Sep 20
Growing season131 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around October 21.

From the NOAA station Cold Bay Airport, AK — 4 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 99571

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 13 – Apr 27
SpinachSow outdoors · Apr 13 – May 4
Broccoli, cabbageStart indoors · Mar 16 – Mar 30
Broccoli, cabbageTransplant · May 4 – May 18
Onion setsPlant outdoors · Apr 27 – May 11
PotatoesPlant outdoors · May 4 – May 18
LettuceSow outdoors · Apr 27 – May 11
Carrots, beetsSow outdoors · May 4 – May 18
TomatoesStart indoors · Mar 30 – Apr 13
TomatoesTransplant · Jun 1 – Jun 15
Peppers, eggplantStart indoors · Mar 16 – Mar 30
Peppers, eggplantTransplant · Jun 8 – Jun 22
BeansSow outdoors · Jun 1 – Jun 15
Sweet cornSow outdoors · Jun 1 – Jun 15
Cucumbers, squashSow outdoors · Jun 1 – Jun 15
Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23
GarlicPlant cloves · Sep 20 – Oct 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 25) and first fall frost (Oct 4) 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 7a in Alaska

289 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Cold Bay, AK.

Soil in Cold Bay, AK

The soil mapped at the center of ZIP 99571 is E25-Maritime tall scrub-ashy till slopes, moderately deep — slightly decomposed plant material, well drained.

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

Map unit: Southern Alaska Peninsula Mountains-Maritime Upland-Glaciated Plains and Hills.

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 99571; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cold Bay, AK

Summer high57 °Faverage high, August
Winter low24 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights148nights a year at 32 °F or less
Growing degree days195base 50 °F — the season’s usable heat
Longest day17 h 26 mindaylight on June 21
Shortest day7 h 06 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation42.7 inper year, rain and melted snow
Snowfall67 inper year; 67 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°32 °FJanuary: average high 33 °F, low 24 °F 33°24° JanFebruary: average high 35 °F, low 26 °F 35°26° FebMarch: average high 35 °F, low 24 °F 35°24° MarApril: average high 40 °F, low 30 °F 40°30° AprMay: average high 47 °F, low 36 °F 47°36° MayJune: average high 52 °F, low 42 °F 52°42° JunJuly: average high 56 °F, low 47 °F 56°47° JulAugust: average high 57 °F, low 48 °F 57°48° AugSeptember: average high 53 °F, low 43 °F 53°43° SepOctober: average high 47 °F, low 36 °F 47°36° OctNovember: average high 40 °F, low 31 °F 40°31° NovDecember: average high 36 °F, low 26 °F 36°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.38 in precipitation, 12.6 in snowfall 3.4❄13 JanFebruary: 3.17 in precipitation, 10 in snowfall 3.2❄10 FebMarch: 2.98 in precipitation, 12.8 in snowfall 3.0❄13 MarApril: 2.70 in precipitation, 6.4 in snowfall 2.7❄6 AprMay: 2.64 in precipitation, 1.2 in snowfall 2.6❄1 MayJune: 2.74 in precipitation 2.7 JunJuly: 2.51 in precipitation 2.5 JulAugust: 3.71 in precipitation 3.7 AugSeptember: 4.50 in precipitation 4.5 SepOctober: 4.93 in precipitation, 2 in snowfall 4.9❄2 OctNovember: 4.99 in precipitation, 8.2 in snowfall 5.0❄8 NovDecember: 4.42 in precipitation, 14.1 in snowfall 4.4❄14 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cold Bay Airport, AK (4 mi away); precipitation: Cold Bay Airport, AK (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 2 nearest ZIP codes share zone 7a.

996127a
King Cove, AK · 23 mi
995837a
False Pass, AK · 35 mi

Alaska planting zones →

Questions about 99571

What planting zone is ZIP code 99571?

ZIP code 99571 (Cold Bay, AK) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Cold Bay, AK?

The median last spring frost (32 °F) near 99571 is May 25; after June 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cold Bay Airport station.

When is the first frost in Cold Bay, AK?

The median first fall frost near 99571 is October 4, giving a median frost-free growing season of 131 days.

When should I plant tomatoes in 99571?

Start tomato seeds indoors around Mar 30 – Apr 13 and set transplants outside around Jun 1 – Jun 15, one to three weeks after the median last frost.

How much rain and snow does 99571 get?

About 42.7 inches of precipitation a year and 67 inches of snowfall (NOAA 1991–2020 normals, Cold Bay Airport station).

How hot do summers get in Cold Bay, AK?

The average high peaks at 57 °F in August, with about 0 days a year at 90 °F or more.

What kind of soil does 99571 have?

The USDA soil survey maps E25-Maritime tall scrub-ashy till slopes, moderately deep at the center of ZIP 99571: slightly decomposed plant material, well drained, pH about 4.4 (strongly acidic).

What kind of onions grow in Cold Bay, AK?

Long-day onions: the longest day near 99571 is 17 h 26 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).