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

Planting zone for 99706 — Fairbanks, AK

ZIP code 99706 (Fairbanks, Fairbanks North Star County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is June 5 and the first fall frost August 21.

Where ZIP 99706 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.

Zone3b−35 to −30 °F
Coldest night−37.2 to −34.4 °C
Last frostJun 5
First frostAug 21
2012 zone2a

Was 2a on the 2012 map — 1.5 zones warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 3b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Fairbanks, 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 Fairbanks, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 5median — 50% chance of a later frost
Safe for tender plantsJune 30only 10% chance of frost after
First fall frostAugust 21median — 10% chance by Aug 8
Growing season75 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 25 and returns around September 1.

From the NOAA station Delta Junction 20 Se, AK — 13 miles away, elevation 1,125 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 99706

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 24 – May 8
SpinachSow outdoors · Apr 24 – May 15
Broccoli, cabbageStart indoors · Mar 27 – Apr 10
Broccoli, cabbageTransplant · May 15 – May 29
Onion setsPlant outdoors · May 8 – May 22
PotatoesPlant outdoors · May 15 – May 29
LettuceSow outdoors · May 8 – May 22
Carrots, beetsSow outdoors · May 15 – May 29
TomatoesStart indoors · Apr 10 – Apr 24
TomatoesTransplant · Jun 12 – Jun 26
Peppers, eggplantStart indoors · Mar 27 – Apr 10
Peppers, eggplantTransplant · Jun 19 – Jul 3
BeansSow outdoors · Jun 12 – Jun 26
Sweet cornSow outdoors · Jun 12 – Jun 26
Cucumbers, squashSow outdoors · Jun 12 – Jun 26
Fall lettuce, spinachSow outdoors · Jun 26 – Jul 10
GarlicPlant cloves · Aug 7 – Sep 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 5) and first fall frost (Aug 21) 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 3b in Alaska

172 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −35 °F or colder — the bottom of zone 3b. 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 32

alpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °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 °Fchokecherry25 ft · blooms mid spring · high shade tolerance · to −43 °F

Wildflowers & perennials 64

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °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 speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican vetch1.3 ft · blooms late spring · high shade tolerance · to −38 °F

Grasses 61

alpine 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 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °Fbearded fescue1.2 ft · blooms late spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late 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 Fairbanks, AK.

Soil in Fairbanks, AK

The soil mapped at the center of ZIP 99706 is E31-Boreal forest-silty slopes — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH3.5strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter75%high
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Interior Alaska Highlands-Boreal Upland-Rounded Mountains, Acid.

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 99706; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Fairbanks, AK

Summer high71 °Faverage high, July
Winter low−13 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights253nights a year at 32 °F or less
Growing degree days657base 50 °F — the season’s usable heat
Longest day21 h 02 mindaylight on June 21
Shortest day4 h 12 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation11.8 inper year, rain and melted snow
Snowfall42 inper year; 152 days with snow on the ground

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°32 °FJanuary: average high 5 °F, low -13 °F 5°−13° JanFebruary: average high 15 °F, low -7 °F 15°−7° FebMarch: average high 26 °F, low -4 °F 26°−4° MarApril: average high 46 °F, low 17 °F 46°17° AprMay: average high 61 °F, low 32 °F 61°32° MayJune: average high 70 °F, low 43 °F 70°43° JunJuly: average high 71 °F, low 46 °F 71°46° JulAugust: average high 66 °F, low 40 °F 66°40° AugSeptember: average high 55 °F, low 30 °F 55°30° SepOctober: average high 34 °F, low 15 °F 34°15° OctNovember: average high 14 °F, low -2 °F 14°−2° NovDecember: average high 8 °F, low -9 °F 8°−9° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 0.39 in precipitation, 6.3 in snowfall 0.4❄6 JanFebruary: 0.29 in precipitation, 5.1 in snowfall 0.3❄5 FebMarch: 0.30 in precipitation, 4.4 in snowfall 0.3❄4 MarApril: 0.28 in precipitation, 2.4 in snowfall 0.3❄2 AprMay: 0.87 in precipitation, 0.5 in snowfall 0.9❄1 MayJune: 2.19 in precipitation 2.2 JunJuly: 2.18 in precipitation 2.2 JulAugust: 2.25 in precipitation 2.3 AugSeptember: 1.17 in precipitation, 1 in snowfall 1.2❄1 SepOctober: 0.75 in precipitation, 8 in snowfall 0.8❄8 OctNovember: 0.59 in precipitation, 7.7 in snowfall 0.6❄8 NovDecember: 0.50 in precipitation, 6.8 in snowfall 0.5❄7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Delta Junction 20 Se, AK (13 mi away); precipitation: Delta Junction 20 Se, AK (13 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

997373a
Delta Junction, AK · 43 mi
997761b
Tanacross, AK · 60 mi
997123b
Fairbanks, AK · 81 mi
995862b
Gakona, AK · 92 mi
997303b
Central, AK · 117 mi

All 10 ZIP codes in Fairbanks → · Alaska planting zones →

Questions about 99706

What planting zone is ZIP code 99706?

ZIP code 99706 (Fairbanks, AK) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Fairbanks, AK?

The median last spring frost (32 °F) near 99706 is June 5; after June 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Delta Junction 20 Se station.

When is the first frost in Fairbanks, AK?

The median first fall frost near 99706 is August 21, giving a median frost-free growing season of 75 days.

When should I plant tomatoes in 99706?

Start tomato seeds indoors around Apr 10 – Apr 24 and set transplants outside around Jun 12 – Jun 26, one to three weeks after the median last frost.

How much rain and snow does 99706 get?

About 11.8 inches of precipitation a year and 42 inches of snowfall (NOAA 1991–2020 normals, Delta Junction 20 Se station).

How hot do summers get in Fairbanks, AK?

The average high peaks at 71 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 99706 have?

The USDA soil survey maps E31-Boreal forest-silty slopes at the center of ZIP 99706: slightly decomposed plant material, well drained, pH about 3.5 (strongly acidic).

What kind of onions grow in Fairbanks, AK?

Long-day onions: the longest day near 99706 is 21 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99706 change?

Yes. The 2012 USDA map put 99706 in zone 2a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.