Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 99576 — Dillingham, AK

ZIP code 99576 (Dillingham, Dillingham (CA) County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 26 and the first fall frost September 15.

Where ZIP 99576 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 frostMay 26

First frostSep 15

2012 zone4b

Was 4b on the 2012 map — half a zone colder now. 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 Dillingham, 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 Dillingham, 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 — 91 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 99576

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.

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 Dillingham, AK.

Soil in Dillingham, AK

The center of ZIP 99576 is mapped as Water: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 99576; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dillingham, 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)

Average high and low, by month

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: King Salmon, AK (91 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

995554b

Aleknagik, AK · 7 mi

995694b

Clarks Point, AK · 40 mi

996284b

Manokotak, AK · 44 mi

995804b

Ekwok, AK · 47 mi

996364b

New Stuyahok, AK · 55 mi

Alaska planting zones →

Questions about 99576

What planting zone is ZIP code 99576?

ZIP code 99576 (Dillingham, 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 Dillingham, AK?

The median last spring frost (32 °F) near 99576 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 Dillingham, AK?

The median first fall frost near 99576 is September 15, giving a median frost-free growing season of 111 days.

When should I plant tomatoes in 99576?

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 hot do summers get in Dillingham, AK?

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

What kind of onions grow in Dillingham, AK?

Long-day onions: the longest day near 99576 is 18 h 38 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99576 change?

Yes. The 2012 USDA map put 99576 in zone 4b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.