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

Planting zone for 99580 — Ekwok, AK

ZIP code 99580 (Ekwok, Dillingham (CA) County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 26 and the first fall frost September 15.

Where ZIP 99580 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.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostMay 26
First frostSep 15
2012 zone4a

Was 4a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ekwok, 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 Ekwok, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 26median — 50% chance of a later frost
Safe for tender plantsJune 11only 10% chance of frost after
First fall frostSeptember 15median — 10% chance by Aug 31
Growing season111 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around September 27.

From the NOAA station King Salmon, AK — 55 miles away, elevation 62 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 99580

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 14 – Apr 28
SpinachSow outdoors · Apr 14 – May 5
Broccoli, cabbageStart indoors · Mar 17 – Mar 31
Broccoli, cabbageTransplant · May 5 – May 19
Onion setsPlant outdoors · Apr 28 – May 12
PotatoesPlant outdoors · May 5 – May 19
LettuceSow outdoors · Apr 28 – May 12
Carrots, beetsSow outdoors · May 5 – May 19
TomatoesStart indoors · Mar 31 – Apr 14
TomatoesTransplant · Jun 2 – Jun 16
Peppers, eggplantStart indoors · Mar 17 – Mar 31
Peppers, eggplantTransplant · Jun 9 – Jun 23
BeansSow outdoors · Jun 2 – Jun 16
Sweet cornSow outdoors · Jun 2 – Jun 16
Cucumbers, squashSow outdoors · Jun 2 – Jun 16
Fall lettuce, spinachSow outdoors · Jul 21 – Aug 4
GarlicPlant cloves · Sep 1 – Oct 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 26) and first fall frost (Sep 15) 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.

Soil in Ekwok, AK

The soil mapped at the center of ZIP 99580 is Iowithla — slightly decomposed plant material, moderately well drained.

TextureSlightly decomposed plant materialtop layer
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter90%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Iowithla-Kokwok complex, 0 to 5 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 99580; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ekwok, AK

Summer high65 °Faverage high, July
Winter low10 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights192nights a year at 32 °F or less
Growing degree days566base 50 °F — the season’s usable heat
Longest day18 h 38 mindaylight on June 21
Shortest day6 h 04 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation21.4 inper year, rain and melted snow
Snowfall47 inper year; 84 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°32 °FJanuary: average high 24 °F, low 10 °F 24°10° JanFebruary: average high 30 °F, low 15 °F 30°15° FebMarch: average high 32 °F, low 15 °F 32°15° MarApril: average high 45 °F, low 28 °F 45°28° AprMay: average high 55 °F, low 36 °F 55°36° MayJune: average high 62 °F, low 44 °F 62°44° JunJuly: average high 65 °F, low 49 °F 65°49° JulAugust: average high 63 °F, low 48 °F 63°48° AugSeptember: average high 56 °F, low 41 °F 56°41° SepOctober: average high 44 °F, low 29 °F 44°29° OctNovember: average high 32 °F, low 18 °F 32°18° NovDecember: average high 26 °F, low 11 °F 26°11° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.93 in precipitation, 8.6 in snowfall 0.9❄9 JanFebruary: 0.91 in precipitation, 7.2 in snowfall 0.9❄7 FebMarch: 0.76 in precipitation, 7.2 in snowfall 0.8❄7 MarApril: 1.04 in precipitation, 4.4 in snowfall 1.0❄4 AprMay: 1.44 in precipitation, 0.6 in snowfall 1.4❄1 MayJune: 1.83 in precipitation 1.8 JunJuly: 2.46 in precipitation 2.5 JulAugust: 3.26 in precipitation 3.3 AugSeptember: 3.40 in precipitation 3.4 SepOctober: 2.31 in precipitation, 2.5 in snowfall 2.3❄3 OctNovember: 1.72 in precipitation, 6.7 in snowfall 1.7❄7 NovDecember: 1.38 in precipitation, 10.2 in snowfall 1.4❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: King Salmon, AK (55 mi away); precipitation: King Salmon, AK (55 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

996364b
New Stuyahok, AK · 12 mi
996254b
Levelock, AK · 28 mi
995554b
Aleknagik, AK · 42 mi
996334b
Naknek, AK · 44 mi
995764a
Dillingham, AK · 47 mi
996704b
South Naknek, AK · 50 mi
995694b
Clarks Point, AK · 53 mi
996284b
Manokotak, AK · 66 mi

Alaska planting zones →

Questions about 99580

What planting zone is ZIP code 99580?

ZIP code 99580 (Ekwok, AK) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Ekwok, AK?

The median last spring frost (32 °F) near 99580 is May 26; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, King Salmon station.

When is the first frost in Ekwok, AK?

The median first fall frost near 99580 is September 15, giving a median frost-free growing season of 111 days.

When should I plant tomatoes in 99580?

Start tomato seeds indoors around Mar 31 – Apr 14 and set transplants outside around Jun 2 – Jun 16, one to three weeks after the median last frost.

How much rain and snow does 99580 get?

About 21.4 inches of precipitation a year and 47 inches of snowfall (NOAA 1991–2020 normals, King Salmon station).

How hot do summers get in Ekwok, AK?

The average high peaks at 65 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 99580 have?

The USDA soil survey maps Iowithla at the center of ZIP 99580: slightly decomposed plant material, moderately well drained, pH about 5.5 (moderately acidic).

What kind of onions grow in Ekwok, AK?

Long-day onions: the longest day near 99580 is 18 h 38 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99580 change?

Yes. The 2012 USDA map put 99580 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.