Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 99613 — King Salmon, AK

ZIP code 99613 (King Salmon, Bristol Bay County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is June 4 and the first fall frost September 12.

Where ZIP 99613 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.

Zone4a−30 to −25 °F

Coldest night−34.4 to −31.7 °C

Last frostJun 4

First frostSep 12

2012 zone4a

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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for King Salmon, 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 King Salmon, AK

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostJune 4median — 50% chance of a later frost

Safe for tender plantsJune 22only 10% chance of frost after

First fall frostSeptember 12median — 10% chance by Aug 28

Growing season98 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around September 26.

From the NOAA station Intricate Bay, AK — 45 miles away, elevation 121 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 99613

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 23 – May 7

SpinachSow outdoors · Apr 23 – May 14

Broccoli, cabbageStart indoors · Mar 26 – Apr 9

Broccoli, cabbageTransplant · May 14 – May 28

Onion setsPlant outdoors · May 7 – May 21

PotatoesPlant outdoors · May 14 – May 28

LettuceSow outdoors · May 7 – May 21

Carrots, beetsSow outdoors · May 14 – May 28

TomatoesStart indoors · Apr 9 – Apr 23

TomatoesTransplant · Jun 11 – Jun 25

Peppers, eggplantStart indoors · Mar 26 – Apr 9

Peppers, eggplantTransplant · Jun 18 – Jul 2

BeansSow outdoors · Jun 11 – Jun 25

Sweet cornSow outdoors · Jun 11 – Jun 25

Cucumbers, squashSow outdoors · Jun 11 – Jun 25

Fall lettuce, spinachSow outdoors · Jul 18 – Aug 1

GarlicPlant cloves · Aug 29 – Oct 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 4) and first fall frost (Sep 12) 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 4a in Alaska

240 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

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 King Salmon, AK.

Soil in King Salmon, AK

The soil mapped at the center of ZIP 99613 is E36-maritime scrub-ashy till slopes — 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 matter80%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Bristol Bay-Northern Alaska Peninsula Lowlands-Maritime Upland-Glaciated Plains, Ash Influenced.

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 99613; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in King Salmon, AK

Summer high66 °Faverage high, July

Winter low10 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights191nights a year at 32 °F or less

Growing degree days529base 50 °F — the season’s usable heat

Longest day18 h 32 mindaylight on June 21

Shortest day6 h 09 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation72.7 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Intricate Bay, AK (45 mi away); precipitation: Mcneil River Sgs, AK (39 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

South Naknek, AK · 64 mi

996474b

Pedro Bay, AK · 72 mi

996534a

Port Alsworth, AK · 83 mi

996087a

Karluk, AK · 109 mi

996404a

Nondalton, AK · 114 mi

Alaska planting zones →

Questions about 99613

What planting zone is ZIP code 99613?

ZIP code 99613 (King Salmon, AK) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in King Salmon, AK?

The median last spring frost (32 °F) near 99613 is June 4; after June 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Intricate Bay station.

When is the first frost in King Salmon, AK?

The median first fall frost near 99613 is September 12, giving a median frost-free growing season of 98 days.

When should I plant tomatoes in 99613?

Start tomato seeds indoors around Apr 9 – Apr 23 and set transplants outside around Jun 11 – Jun 25, one to three weeks after the median last frost.

How much rain and snow does 99613 get?

About 72.7 inches of precipitation a year (NOAA 1991–2020 normals, Mcneil River Sgs station).

How hot do summers get in King Salmon, AK?

The average high peaks at 66 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 99613 have?

The USDA soil survey maps E36-maritime scrub-ashy till slopes at the center of ZIP 99613: slightly decomposed plant material, well drained, pH about 4.4 (strongly acidic).

What kind of onions grow in King Salmon, AK?

Long-day onions: the longest day near 99613 is 18 h 32 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).