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

Planting zone for 99726 — Bettles Field, AK

ZIP code 99726 (Bettles Field, Yukon-Koyukuk (CA) County) is in USDA zone 1b: the coldest winter night averages −55 to −50 °F. The median last spring frost is May 22 and the first fall frost August 24.

Where ZIP 99726 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.

Zone1b−55 to −50 °F
Coldest night−48.3 to −45.6 °C
Last frostMay 22
First frostAug 24
2012 zone1b

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 1b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Bettles Field, 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 Bettles Field, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 22median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostAugust 24median — 10% chance by Aug 10
Growing season94 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 13 and returns around September 5.

From the NOAA station Bettles Airport, AK — 11 miles away, elevation 643 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 99726

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 10 – Apr 24
SpinachSow outdoors · Apr 10 – May 1
Broccoli, cabbageStart indoors · Mar 13 – Mar 27
Broccoli, cabbageTransplant · May 1 – May 15
Onion setsPlant outdoors · Apr 24 – May 8
PotatoesPlant outdoors · May 1 – May 15
LettuceSow outdoors · Apr 24 – May 8
Carrots, beetsSow outdoors · May 1 – May 15
TomatoesStart indoors · Mar 27 – Apr 10
TomatoesTransplant · May 29 – Jun 12
Peppers, eggplantStart indoors · Mar 13 – Mar 27
Peppers, eggplantTransplant · Jun 5 – Jun 19
BeansSow outdoors · May 29 – Jun 12
Sweet cornSow outdoors · May 29 – Jun 12
Cucumbers, squashSow outdoors · May 29 – Jun 12
Fall lettuce, spinachSow outdoors · Jun 29 – Jul 13
GarlicPlant cloves · Aug 10 – Sep 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 22) and first fall frost (Aug 24) 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 1b in Alaska

37 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −55 °F or colder — the bottom of zone 1b. Each links to its USDA PLANTS profile.

Trees 7

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 °Ftamarack80 ft · blooms mid spring · high shade tolerance · to −79 °F

Shrubs 15

alpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °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 °Fmarsh Labrador tea0.5 ft · blooms summer · to −62 °Fnetleaf willow0.2 ft · blooms early summer · to −62 °F

Wildflowers & perennials 11

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 raspberry1 ft · blooms summer · high shade tolerance · to −62 °Feightpetal mountain-avens0.3 ft · blooms late spring · medium shade tolerance · to −62 °Fhigh northern buttercup1 ft · blooms summer · high shade tolerance · to −62 °F

Grasses 2

arctic bluegrass2 ft · high shade tolerance · to −62 °Flivid sedge1 ft · blooms early summer · high shade tolerance · to −62 °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 Bettles Field, AK.

Soil in Bettles Field, AK

The soil mapped at the center of ZIP 99726 is E31-Boreal taiga-silty frozen slopes — peat, poorly drained.

TexturePeattop layer
pH4.3strongly acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter90%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Interior Alaska Highlands-Boreal Upland-Loess Plains and Peat Plateaus.

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 99726; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Bettles Field, AK

Summer high70 °Faverage high, June
Winter low−19 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights239nights a year at 32 °F or less
Growing degree days754base 50 °F — the season’s usable heat
Longest day24 h 00 mindaylight on June 21
Shortest day1 h 54 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation16 inper year, rain and melted snow
Snowfall98 inper year; 214 days with snow on the ground

Average high and low, by month

−30°−20°−10°0°10°20°30°40°50°60°70°80°32 °FJanuary: average high -2 °F, low -19 °F −2°−19° JanFebruary: average high 7 °F, low -13 °F 7°−13° FebMarch: average high 17 °F, low -9 °F 17°−9° MarApril: average high 36 °F, low 13 °F 36°13° AprMay: average high 56 °F, low 34 °F 56°34° MayJune: average high 70 °F, low 47 °F 70°47° JunJuly: average high 70 °F, low 49 °F 70°49° JulAugust: average high 63 °F, low 43 °F 63°43° AugSeptember: average high 50 °F, low 33 °F 50°33° SepOctober: average high 28 °F, low 14 °F 28°14° OctNovember: average high 8 °F, low -7 °F 8°−7° NovDecember: average high 2 °F, low -14 °F 2°−14° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 0.87 in precipitation, 14 in snowfall 0.9❄14 JanFebruary: 0.96 in precipitation, 15.9 in snowfall 1.0❄16 FebMarch: 0.61 in precipitation, 9.3 in snowfall 0.6❄9 MarApril: 0.60 in precipitation, 5.2 in snowfall 0.6❄5 AprMay: 0.89 in precipitation, 1 in snowfall 0.9❄1 MayJune: 1.46 in precipitation 1.5 JunJuly: 2.32 in precipitation 2.3 JulAugust: 2.71 in precipitation 2.7 AugSeptember: 2.13 in precipitation, 3.2 in snowfall 2.1❄3 SepOctober: 1.17 in precipitation, 12 in snowfall 1.2❄12 OctNovember: 1.15 in precipitation, 19.1 in snowfall 1.1❄19 NovDecember: 1.14 in precipitation, 18.2 in snowfall 1.1❄18 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Bettles Airport, AK (11 mi away); precipitation: Bettles Airport, AK (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

2 of the 3 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

997201a
Allakaket, AK · 39 mi
997671b
Rampart, AK · 94 mi
997212b
Anaktuvuk Pass, AK · 97 mi

Alaska planting zones →

Questions about 99726

What planting zone is ZIP code 99726?

ZIP code 99726 (Bettles Field, AK) is in USDA hardiness zone 1b on the 2023 map: the coldest night of an average winter reaches −55 to −50 °F (−48.3 to −45.6 °C).

When is the last frost in Bettles Field, AK?

The median last spring frost (32 °F) near 99726 is May 22; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Bettles Airport station.

When is the first frost in Bettles Field, AK?

The median first fall frost near 99726 is August 24, giving a median frost-free growing season of 94 days.

When should I plant tomatoes in 99726?

Start tomato seeds indoors around Mar 27 – Apr 10 and set transplants outside around May 29 – Jun 12, one to three weeks after the median last frost.

How much rain and snow does 99726 get?

About 16 inches of precipitation a year and 98 inches of snowfall (NOAA 1991–2020 normals, Bettles Airport station).

How hot do summers get in Bettles Field, AK?

The average high peaks at 70 °F in June, with about 0 days a year at 90 °F or more.

What kind of soil does 99726 have?

The USDA soil survey maps E31-Boreal taiga-silty frozen slopes at the center of ZIP 99726: peat, poorly drained, pH about 4.3 (strongly acidic).

What kind of onions grow in Bettles Field, AK?

Long-day onions: the longest day near 99726 is 24 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).