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

Planting zone for 99549 — Port Heiden, AK

ZIP code 99549 (Port Heiden, Lake and Peninsula County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F.

Where ZIP 99549 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostrare
First frostrare
2012 zone5b

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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Port Heiden, 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

No NOAA station with frost records lies within 90 miles of Port Heiden, AK, so we don't show frost dates here rather than guess. Your local extension office can give you a date.

Native plants for zone 5b in Alaska

282 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 47

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 122

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 88

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 Port Heiden, AK.

Soil in Port Heiden, AK

The soil mapped at the center of ZIP 99549 is E25-Maritime tall scrub-sandy volcanic slopes — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer
pH6.8neutral; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter75%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Southern Alaska Peninsula Mountains-Maritime Upland-Volcanic Mountains and Lowland-Flood Plains and Stream Terraces.

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 99549; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Port Heiden, AK

Longest day17 h 53 mindaylight on June 21
Shortest day6 h 43 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

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.

995656a
Chignik Lagoon, AK · 46 mi
995646b
Chignik, AK · 47 mi
995486b
Chignik Lake, AK · 49 mi
996495a
Pilot Point, AK · 61 mi
996486b
Perryville, AK · 74 mi
996956b
Anchorage, AK · 80 mi
995795a
Egegik, AK · 97 mi

Alaska planting zones →

Questions about 99549

What planting zone is ZIP code 99549?

ZIP code 99549 (Port Heiden, AK) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

What kind of soil does 99549 have?

The USDA soil survey maps E25-Maritime tall scrub-sandy volcanic slopes at the center of ZIP 99549: slightly decomposed plant material, somewhat excessively drained, pH about 6.8 (neutral).

What kind of onions grow in Port Heiden, AK?

Long-day onions: the longest day near 99549 is 17 h 53 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).