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

Planting zone for 99712 — Fairbanks, AK

ZIP code 99712 (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 30 and the first fall frost September 2.

Where ZIP 99712 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 30
First frostSep 2
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 30median — 50% chance of a later frost
Safe for tender plantsJune 13only 10% chance of frost after
First fall frostSeptember 2median — 10% chance by Aug 13
Growing season95 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 16 and returns around September 16.

From the NOAA station Two Rivers, AK — 33 miles away, elevation 604 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 99712

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 18 – May 2
SpinachSow outdoors · Apr 18 – May 9
Broccoli, cabbageStart indoors · Mar 21 – Apr 4
Broccoli, cabbageTransplant · May 9 – May 23
Onion setsPlant outdoors · May 2 – May 16
PotatoesPlant outdoors · May 9 – May 23
LettuceSow outdoors · May 2 – May 16
Carrots, beetsSow outdoors · May 9 – May 23
TomatoesStart indoors · Apr 4 – Apr 18
TomatoesTransplant · Jun 6 – Jun 20
Peppers, eggplantStart indoors · Mar 21 – Apr 4
Peppers, eggplantTransplant · Jun 13 – Jun 27
BeansSow outdoors · Jun 6 – Jun 20
Sweet cornSow outdoors · Jun 6 – Jun 20
Cucumbers, squashSow outdoors · Jun 6 – Jun 20
Fall lettuce, spinachSow outdoors · Jul 8 – Jul 22
GarlicPlant cloves · Aug 19 – Sep 23
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 30) and first fall frost (Sep 2) 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 99712 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 99712; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Fairbanks, AK

Summer high75 °Faverage high, July
Winter low−13 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights236nights a year at 32 °F or less
Growing degree days982base 50 °F — the season’s usable heat
Longest day22 h 07 mindaylight on June 21
Shortest day3 h 32 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation20.6 inper year, rain and melted snow

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 6 °F, low -13 °F 6°−13° JanFebruary: average high 18 °F, low -4 °F 18°−4° FebMarch: average high 29 °F, low 1 °F 29°1° MarApril: average high 49 °F, low 22 °F 49°22° AprMay: average high 65 °F, low 34 °F 65°34° MayJune: average high 74 °F, low 45 °F 74°45° JunJuly: average high 75 °F, low 49 °F 75°49° JulAugust: average high 68 °F, low 44 °F 68°44° AugSeptember: average high 56 °F, low 34 °F 56°34° SepOctober: average high 36 °F, low 18 °F 36°18° OctNovember: average high 16 °F, low -2 °F 16°−2° NovDecember: average high 9 °F, low -10 °F 9°−10° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 0.83 in precipitation 0.8 JanFebruary: 0.83 in precipitation 0.8 FebMarch: 0.69 in precipitation 0.7 MarApril: 0.58 in precipitation 0.6 AprMay: 1.16 in precipitation 1.2 MayJune: 2.75 in precipitation 2.8 JunJuly: 3.77 in precipitation 3.8 JulAugust: 4.15 in precipitation 4.2 AugSeptember: 2.45 in precipitation 2.5 SepOctober: 1.52 in precipitation 1.5 OctNovember: 1.14 in precipitation 1.1 NovDecember: 0.74 in precipitation 0.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Two Rivers, AK (33 mi away); precipitation: Monument Creek, 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.

997073b
Fairbanks, AK · 12 mi
997162a
Two Rivers, AK · 31 mi
997303b
Central, AK · 42 mi
997022a
Eielson Afb, AK · 43 mi
997052a
North Pole, AK · 44 mi
997143b
Salcha, AK · 50 mi
997312a
Fort Greely, AK · 78 mi
997063b
Fairbanks, AK · 81 mi

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

Questions about 99712

What planting zone is ZIP code 99712?

ZIP code 99712 (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 99712 is May 30; after June 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Two Rivers station.

When is the first frost in Fairbanks, AK?

The median first fall frost near 99712 is September 2, giving a median frost-free growing season of 95 days.

When should I plant tomatoes in 99712?

Start tomato seeds indoors around Apr 4 – Apr 18 and set transplants outside around Jun 6 – Jun 20, one to three weeks after the median last frost.

How much rain and snow does 99712 get?

About 20.6 inches of precipitation a year (NOAA 1991–2020 normals, Monument Creek station).

How hot do summers get in Fairbanks, AK?

The average high peaks at 75 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 99712 have?

The USDA soil survey maps E31-Boreal forest-silty slopes at the center of ZIP 99712: 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 99712 is 22 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99712 change?

Yes. The 2012 USDA map put 99712 in zone 2a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.