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

Planting zone for 99707 — Fairbanks, AK

ZIP code 99707 (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 May 28 and the first fall frost August 26.

Where ZIP 99707 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 frostMay 28
First frostAug 26
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 frostMay 28median — 50% chance of a later frost
Safe for tender plantsJune 19only 10% chance of frost after
First fall frostAugust 26median — 10% chance by Aug 9
Growing season87 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 14 and returns around September 6.

From the NOAA station Mile 42 Steese, AK — 27 miles away, elevation 961 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 99707

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 16 – Apr 30
SpinachSow outdoors · Apr 16 – May 7
Broccoli, cabbageStart indoors · Mar 19 – Apr 2
Broccoli, cabbageTransplant · May 7 – May 21
Onion setsPlant outdoors · Apr 30 – May 14
PotatoesPlant outdoors · May 7 – May 21
LettuceSow outdoors · Apr 30 – May 14
Carrots, beetsSow outdoors · May 7 – May 21
TomatoesStart indoors · Apr 2 – Apr 16
TomatoesTransplant · Jun 4 – Jun 18
Peppers, eggplantStart indoors · Mar 19 – Apr 2
Peppers, eggplantTransplant · Jun 11 – Jun 25
BeansSow outdoors · Jun 4 – Jun 18
Sweet cornSow outdoors · Jun 4 – Jun 18
Cucumbers, squashSow outdoors · Jun 4 – Jun 18
Fall lettuce, spinachSow outdoors · Jul 1 – Jul 15
GarlicPlant cloves · Aug 12 – Sep 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 28) and first fall frost (Aug 26) 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 99707 is Histic Pergelic Cryaquepts — peat, poorly drained.

TexturePeattop layer
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter90%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Histic Pergelic Cryaquepts-Typic Cryochrepts complex, 15 to 45 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 99707; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Fairbanks, AK

Summer high70 °Faverage high, July
Winter low−11 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights247nights a year at 32 °F or less
Growing degree days662base 50 °F — the season’s usable heat
Longest day22 h 15 mindaylight on June 21
Shortest day3 h 28 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation19 inper year, rain and melted snow

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°32 °FJanuary: average high 6 °F, low -11 °F 6°−11° JanFebruary: average high 14 °F, low -5 °F 14°−5° FebMarch: average high 24 °F, low -1 °F 24°−1° MarApril: average high 43 °F, low 19 °F 43°19° AprMay: average high 58 °F, low 34 °F 58°34° MayJune: average high 69 °F, low 44 °F 69°44° JunJuly: average high 70 °F, low 47 °F 70°47° JulAugust: average high 64 °F, low 41 °F 64°41° AugSeptember: average high 53 °F, low 31 °F 53°31° 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 -7 °F 8°−7° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.79 in precipitation 0.8 JanFebruary: 0.91 in precipitation 0.9 FebMarch: 0.85 in precipitation 0.8 MarApril: 0.67 in precipitation 0.7 AprMay: 0.94 in precipitation 0.9 MayJune: 2.64 in precipitation 2.6 JunJuly: 3.58 in precipitation 3.6 JulAugust: 3.30 in precipitation 3.3 AugSeptember: 2.23 in precipitation 2.2 SepOctober: 1.27 in precipitation 1.3 OctNovember: 1.01 in precipitation 1.0 NovDecember: 0.78 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mile 42 Steese, AK (27 mi away); precipitation: Mt. Ryan, AK (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

997123b
Fairbanks, AK · 12 mi
997162a
Two Rivers, AK · 27 mi
997303b
Central, AK · 39 mi
997052a
North Pole, AK · 40 mi
997022a
Eielson Afb, AK · 42 mi
997032a
Fort Wainwright, AK · 46 mi
997102b
Fairbanks, AK · 48 mi
997112a
Fairbanks, AK · 48 mi

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

Questions about 99707

What planting zone is ZIP code 99707?

ZIP code 99707 (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 99707 is May 28; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mile 42 Steese station.

When is the first frost in Fairbanks, AK?

The median first fall frost near 99707 is August 26, giving a median frost-free growing season of 87 days.

When should I plant tomatoes in 99707?

Start tomato seeds indoors around Apr 2 – Apr 16 and set transplants outside around Jun 4 – Jun 18, one to three weeks after the median last frost.

How much rain and snow does 99707 get?

About 19 inches of precipitation a year (NOAA 1991–2020 normals, Mt. Ryan station).

How hot do summers get in Fairbanks, AK?

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

What kind of soil does 99707 have?

The USDA soil survey maps Histic Pergelic Cryaquepts at the center of ZIP 99707: peat, poorly drained, pH about 5.0 (strongly acidic).

What kind of onions grow in Fairbanks, AK?

Long-day onions: the longest day near 99707 is 22 h 15 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99707 change?

Yes. The 2012 USDA map put 99707 in zone 2a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.