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

Planting zone for 99668 — Sleetmute, AK

ZIP code 99668 (Sleetmute, Bethel Census Area County) is in USDA zone 2b: the coldest winter night averages −45 to −40 °F.

Where ZIP 99668 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.

Zone2b−45 to −40 °F
Coldest night−42.8 to −40 °C
Last frostrare
First frostrare
2012 zone2a

Was 2a 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 2b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Sleetmute, 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 Sleetmute, 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 2b in Alaska

45 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −45 °F or colder — the bottom of zone 2b. Each links to its USDA PLANTS profile.

Trees 8

balsam 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 °Fpaper birch70 ft · blooms mid spring · high shade tolerance · to −62 °Fquaking aspen65 ft · blooms mid spring · high shade tolerance · to −70 °Fsubalpine fir90 ft · blooms late spring · low shade tolerance · to −51 °F

Shrubs 17

alpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °Fblack hawthorn15 ft · blooms mid spring · medium shade tolerance · to −47 °Fhalberd willow3 ft · blooms early summer · to −62 °FLapland rosebay3 ft · blooms late spring · low shade tolerance · to −62 °Flingonberry0.5 ft · blooms summer · high shade tolerance · to −62 °FMacKenzie's willow45 ft · blooms early spring · high shade tolerance · to −50 °F

Wildflowers & perennials 12

alpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °Farctic dock1 ft · blooms summer · high shade tolerance · to −62 °Farctic lupine2 ft · blooms spring · medium shade tolerance · to −62 °Farctic poppy1.5 ft · blooms summer · low shade tolerance · to −54 °Farctic raspberry1 ft · blooms summer · high shade tolerance · to −62 °Feightpetal mountain-avens0.3 ft · blooms late spring · medium shade tolerance · to −62 °F

Grasses 6

arctic bluegrass2 ft · high shade tolerance · to −62 °FHoppner's sedge1 ft · high shade tolerance · to −52 °Flargeflower speargrass2 ft · high shade tolerance · to −52 °Flivid sedge1 ft · blooms early summer · high shade tolerance · to −62 °FLyngbye's sedge1 ft · high shade tolerance · to −52 °FRamensk's sedge1 ft · high shade tolerance · to −52 °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 Sleetmute, AK.

Soil in Sleetmute, AK

The soil mapped at the center of ZIP 99668 is 29-Boreal forest, loamy flood plains — moderately decomposed plant material, moderately well drained.

TextureModerately decomposed plant materialtop layer
pH6.5neutral; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter80%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Boreal Flood Plains.

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 99668; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sleetmute, AK

Longest day19 h 35 mindaylight on June 21
Shortest day5 h 17 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

5 of the 5 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

996563a
Red Devil, AK · 17 mi
995753a
Crooked Creek, AK · 33 mi
995033a
Anchorage, AK · 44 mi
996404a
Nondalton, AK · 82 mi
996752a
Takotna, AK · 98 mi

Alaska planting zones →

Questions about 99668

What planting zone is ZIP code 99668?

ZIP code 99668 (Sleetmute, AK) is in USDA hardiness zone 2b on the 2023 map: the coldest night of an average winter reaches −45 to −40 °F (−42.8 to −40 °C).

What kind of soil does 99668 have?

The USDA soil survey maps 29-Boreal forest, loamy flood plains at the center of ZIP 99668: moderately decomposed plant material, moderately well drained, pH about 6.5 (neutral).

What kind of onions grow in Sleetmute, AK?

Long-day onions: the longest day near 99668 is 19 h 35 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99668 change?

Yes. The 2012 USDA map put 99668 in zone 2a; the 2023 map puts it in zone 2b. The newer map uses 1991–2020 data and more weather stations.