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

Planting zone for 99775 — Fairbanks, AK

ZIP code 99775 (Fairbanks, Fairbanks North Star County) is in USDA zone 2b: the coldest winter night averages −45 to −40 °F. The median last spring frost is May 18 and the first fall frost September 6.

Where ZIP 99775 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.

Zone2b−45 to −40 °F

Coldest night−42.8 to −40 °C

Last frostMay 18

First frostSep 6

2012 zone2a

Was 2a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 2b 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 18median — 50% chance of a later frost

Safe for tender plantsJune 1only 10% chance of frost after

First fall frostSeptember 6median — 10% chance by Aug 24

Growing season111 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 7 and returns around September 20.

From the NOAA station College Obsy, AK — within 1 mile, elevation 597 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 99775

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 6 – Apr 20

SpinachSow outdoors · Apr 6 – Apr 27

Broccoli, cabbageStart indoors · Mar 9 – Mar 23

Broccoli, cabbageTransplant · Apr 27 – May 11

Onion setsPlant outdoors · Apr 20 – May 4

PotatoesPlant outdoors · Apr 27 – May 11

LettuceSow outdoors · Apr 20 – May 4

Carrots, beetsSow outdoors · Apr 27 – May 11

TomatoesStart indoors · Mar 23 – Apr 6

TomatoesTransplant · May 25 – Jun 8

Peppers, eggplantStart indoors · Mar 9 – Mar 23

Peppers, eggplantTransplant · Jun 1 – Jun 15

BeansSow outdoors · May 25 – Jun 8

Sweet cornSow outdoors · May 25 – Jun 8

Cucumbers, squashSow outdoors · May 25 – Jun 8

Fall lettuce, spinachSow outdoors · Jul 12 – Jul 26

GarlicPlant cloves · Aug 23 – Sep 27

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 18) and first fall frost (Sep 6) 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 2b in Alaska

45 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −45 °F or colder — the bottom of zone 2b. 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 99775 is Fairbanks — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter90%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Fairbanks silt loam, 12 to 20 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 99775; 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−11 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights229nights a year at 32 °F or less

Growing degree days906base 50 °F — the season’s usable heat

Longest day21 h 52 mindaylight on June 21

Shortest day3 h 41 mindaylight on December 21

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

Precipitation13.3 inper year, rain and melted snow

Snowfall64 inper year; 193 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: College Obsy, AK (within 1 mile); precipitation: College Obsy, AK (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

Fort Wainwright, AK · 6 mi

997093b

Fairbanks, AK · 9 mi

997052a

North Pole, AK · 18 mi

997022a

Eielson Afb, AK · 27 mi

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

Questions about 99775

What planting zone is ZIP code 99775?

ZIP code 99775 (Fairbanks, AK) is in USDA hardiness zone 2b on the 2023 map: the coldest night of an average winter reaches −45 to −40 °F (−42.8 to −40 °C).

When is the last frost in Fairbanks, AK?

The median last spring frost (32 °F) near 99775 is May 18; after June 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, College Obsy station.

When is the first frost in Fairbanks, AK?

The median first fall frost near 99775 is September 6, giving a median frost-free growing season of 111 days.

When should I plant tomatoes in 99775?

Start tomato seeds indoors around Mar 23 – Apr 6 and set transplants outside around May 25 – Jun 8, one to three weeks after the median last frost.

How much rain and snow does 99775 get?

About 13.3 inches of precipitation a year and 64 inches of snowfall (NOAA 1991–2020 normals, College Obsy 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 99775 have?

The USDA soil survey maps Fairbanks at the center of ZIP 99775: slightly decomposed plant material, well drained, pH about 5.8 (moderately acidic).

What kind of onions grow in Fairbanks, AK?

Long-day onions: the longest day near 99775 is 21 h 52 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99775 change?

Yes. The 2012 USDA map put 99775 in zone 2a; the 2023 map puts it in zone 2b. The newer map uses 1991–2020 data and more weather stations.