Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 99701 — Fairbanks, AK

ZIP code 99701 (Fairbanks, Fairbanks North Star County) is in USDA zone 3a: the coldest winter night averages −40 to −35 °F. The median last spring frost is May 22 and the first fall frost August 24.

Where ZIP 99701 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.

Zone3a−40 to −35 °F

Coldest night−40 to −37.2 °C

Last frostMay 22

First frostAug 24

2012 zone2a

Was 2a on the 2012 map — a full zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 3a 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 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 — 57 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 99701

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 3a in Alaska

80 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −40 °F or colder — the bottom of zone 3a. Each links to its USDA PLANTS profile.

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 99701 is E34-Boreal alpine dwarf scrub-gravelly colluvial slopes — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH4.7strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter70%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Interior Brooks Range Mountains-Boreal Alpine and Subalpine-Rounded Mountains.

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 99701; 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, June

Winter low−19 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights258nights a year at 32 °F or less

Growing degree days565base 50 °F — the season’s usable heat

Longest day24 h 00 mindaylight on June 21

Shortest day0 h 19 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation15.9 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

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

Nearby ZIP codes

1 of the 1 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

997741a

Stevens Village, AK · 95 mi

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

Questions about 99701

What planting zone is ZIP code 99701?

ZIP code 99701 (Fairbanks, AK) is in USDA hardiness zone 3a on the 2023 map: the coldest night of an average winter reaches −40 to −35 °F (−40 to −37.2 °C).

When is the last frost in Fairbanks, AK?

The median last spring frost (32 °F) near 99701 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 Fairbanks, AK?

The median first fall frost near 99701 is August 24, giving a median frost-free growing season of 94 days.

When should I plant tomatoes in 99701?

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 99701 get?

About 15.9 inches of precipitation a year (NOAA 1991–2020 normals, Wiseman station).

How hot do summers get in Fairbanks, 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 99701 have?

The USDA soil survey maps E34-Boreal alpine dwarf scrub-gravelly colluvial slopes at the center of ZIP 99701: slightly decomposed plant material, well drained, pH about 4.7 (strongly acidic).

What kind of onions grow in Fairbanks, AK?

Long-day onions: the longest day near 99701 is 24 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99701 change?

Yes. The 2012 USDA map put 99701 in zone 2a; the 2023 map puts it in zone 3a. The newer map uses 1991–2020 data and more weather stations.