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

Planting zone for 99708 — Fairbanks, AK

ZIP code 99708 (Fairbanks, Fairbanks North Star County) is in USDA zone 2a: the coldest winter night averages −50 to −45 °F. The median last spring frost is May 13 and the first fall frost September 15.

Where ZIP 99708 is

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.

Zone2a−50 to −45 °F
Coldest night−45.6 to −42.8 °C
Last frostMay 13
First frostSep 15
2012 zone2b

Was 2b 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 2a 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 frostMay 13median — 50% chance of a later frost
Safe for tender plantsMay 31only 10% chance of frost after
First fall frostSeptember 15median — 10% chance by Aug 29
Growing season122 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 5 and returns around September 25.

From the NOAA station College 5 Nw, AK — 2 miles away, elevation 978 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 99708

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 1 – Apr 15
SpinachSow outdoors · Apr 1 – Apr 22
Broccoli, cabbageStart indoors · Mar 4 – Mar 18
Broccoli, cabbageTransplant · Apr 22 – May 6
Onion setsPlant outdoors · Apr 15 – Apr 29
PotatoesPlant outdoors · Apr 22 – May 6
LettuceSow outdoors · Apr 15 – Apr 29
Carrots, beetsSow outdoors · Apr 22 – May 6
TomatoesStart indoors · Mar 18 – Apr 1
TomatoesTransplant · May 20 – Jun 3
Peppers, eggplantStart indoors · Mar 4 – Mar 18
Peppers, eggplantTransplant · May 27 – Jun 10
BeansSow outdoors · May 20 – Jun 3
Sweet cornSow outdoors · May 20 – Jun 3
Cucumbers, squashSow outdoors · May 20 – Jun 3
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 13) 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 2a in Alaska

44 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −50 °F or colder — the bottom of zone 2a. 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 16

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 °FMacKenzie's willow45 ft · blooms early spring · high shade tolerance · to −50 °Fmarsh Labrador tea0.5 ft · blooms summer · to −62 °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 Fairbanks, AK.

Soil in Fairbanks, AK

The soil mapped at the center of ZIP 99708 is Gilmore — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter90%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Gilmore silt loam, 20 to 30 percent slopes.

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 99708; 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−6 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights219nights a year at 32 °F or less
Growing degree days934base 50 °F — the season’s usable heat
Longest day21 h 58 mindaylight on June 21
Shortest day3 h 37 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation13.9 inper year, rain and melted snow
Snowfall62 inper year; 196 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 7 °F, low -6 °F 7°−6° JanFebruary: average high 16 °F, low 0 °F 16°0° FebMarch: average high 25 °F, low 5 °F 25°5° MarApril: average high 44 °F, low 23 °F 44°23° AprMay: average high 60 °F, low 38 °F 60°38° MayJune: average high 70 °F, low 49 °F 70°49° JunJuly: average high 71 °F, low 52 °F 71°52° JulAugust: average high 65 °F, low 46 °F 65°46° AugSeptember: average high 54 °F, low 37 °F 54°37° SepOctober: average high 34 °F, low 21 °F 34°21° OctNovember: average high 16 °F, low 4 °F 16°4° NovDecember: average high 10 °F, low -2 °F 10°−2° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.66 in precipitation, 11.9 in snowfall 0.7❄12 JanFebruary: 0.56 in precipitation, 5.2 in snowfall 0.6❄5 FebMarch: 0.41 in precipitation, 6 in snowfall 0.4❄6 MarApril: 0.32 in precipitation, 2.8 in snowfall 0.3❄3 AprMay: 0.74 in precipitation, 1.1 in snowfall 0.7❄1 MayJune: 1.92 in precipitation 1.9 JunJuly: 3.01 in precipitation 3.0 JulAugust: 2.31 in precipitation 2.3 AugSeptember: 1.69 in precipitation, 2.6 in snowfall 1.7❄3 SepOctober: 0.80 in precipitation, 11.6 in snowfall 0.8❄12 OctNovember: 0.83 in precipitation, 9.9 in snowfall 0.8❄10 NovDecember: 0.69 in precipitation, 10.4 in snowfall 0.7❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: College 5 Nw, AK (2 mi away); precipitation: College 5 Nw, AK (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

997752b
Fairbanks, AK · 6 mi
997253b
Ester, AK · 8 mi
997102b
Fairbanks, AK · 9 mi
997112a
Fairbanks, AK · 9 mi
997093b
Fairbanks, AK · 10 mi
997032a
Fort Wainwright, AK · 10 mi
997052a
North Pole, AK · 21 mi
997022a
Eielson Afb, AK · 31 mi

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

Questions about 99708

What planting zone is ZIP code 99708?

ZIP code 99708 (Fairbanks, AK) is in USDA hardiness zone 2a on the 2023 map: the coldest night of an average winter reaches −50 to −45 °F (−45.6 to −42.8 °C).

When is the last frost in Fairbanks, AK?

The median last spring frost (32 °F) near 99708 is May 13; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, College 5 Nw station.

When is the first frost in Fairbanks, AK?

The median first fall frost near 99708 is September 15, giving a median frost-free growing season of 122 days.

When should I plant tomatoes in 99708?

Start tomato seeds indoors around Mar 18 – Apr 1 and set transplants outside around May 20 – Jun 3, one to three weeks after the median last frost.

How much rain and snow does 99708 get?

About 13.9 inches of precipitation a year and 62 inches of snowfall (NOAA 1991–2020 normals, College 5 Nw 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 99708 have?

The USDA soil survey maps Gilmore at the center of ZIP 99708: slightly decomposed plant material, well drained, pH about 5.5 (moderately acidic).

What kind of onions grow in Fairbanks, AK?

Long-day onions: the longest day near 99708 is 21 h 58 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99708 change?

Yes. The 2012 USDA map put 99708 in zone 2b; the 2023 map puts it in zone 2a. The newer map uses 1991–2020 data and more weather stations.