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

Planting zone for Juneau, AK

Juneau, AK is in USDA zones 6a to 7a across its 6 ZIP codes. The median last spring frost is April 20 and the first fall frost October 22.

Juneau on the zone map

Outlined: its 2 ZIP code areas · 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.

Zones6a–7a−10 to 5 °F
ZIP codes6
Last frostApr 20
First frostOct 22
Growing season183 days

6a 1 ZIP   7a 5 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Juneau, 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 Juneau, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 20median — 50% chance of a later frost
Safe for tender plantsMay 5only 10% chance of frost after
First fall frostOctober 22median — 10% chance by Oct 5
Growing season183 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 2 and returns around November 8.

From the NOAA station Juneau Dwtn, AK, elevation 49 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 Juneau

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 9 – Mar 23
SpinachSow outdoors · Mar 9 – Mar 30
Broccoli, cabbageStart indoors · Feb 9 – Feb 23
Broccoli, cabbageTransplant · Mar 30 – Apr 13
Onion setsPlant outdoors · Mar 23 – Apr 6
PotatoesPlant outdoors · Mar 30 – Apr 13
LettuceSow outdoors · Mar 23 – Apr 6
Carrots, beetsSow outdoors · Mar 30 – Apr 13
TomatoesStart indoors · Feb 23 – Mar 9
TomatoesTransplant · Apr 27 – May 11
Peppers, eggplantStart indoors · Feb 9 – Feb 23
Peppers, eggplantTransplant · May 4 – May 18
BeansSow outdoors · Apr 27 – May 11
Sweet cornSow outdoors · Apr 27 – May 11
Cucumbers, squashSow outdoors · Apr 27 – May 11
Fall lettuce, spinachSow outdoors · Aug 27 – Sep 10
GarlicPlant cloves · Oct 8 – Nov 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 22) 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 6a in Alaska

285 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 16

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °Fbalsam 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 °Fmountain hemlock125 ft · blooms early summer · low shade tolerance · to −18 °FPacific silver fir165 ft · blooms late spring · low shade tolerance · to −28 °F

Shrubs 49

alpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °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 °F

Wildflowers & perennials 123

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine aster0.3 ft · blooms early summer · medium shade tolerance · to −28 °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 alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °F

Grasses 88

Alaska brome5 ft · blooms late spring · low shade tolerance · to −18 °FAlaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine 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 °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 Juneau, AK.

Soil in Juneau, AK

The center of ZIP 99812 is mapped as Water, Saline: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 99812; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Juneau, AK

Summer high63 °Faverage high, July
Winter low27 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights105nights a year at 32 °F or less
Growing degree days750base 50 °F — the season’s usable heat
Longest day18 h 17 mindaylight on June 21
Shortest day6 h 22 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation89.6 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°32 °FJanuary: average high 34 °F, low 27 °F 34°27° JanFebruary: average high 37 °F, low 28 °F 37°28° FebMarch: average high 39 °F, low 30 °F 39°30° MarApril: average high 49 °F, low 36 °F 49°36° AprMay: average high 57 °F, low 43 °F 57°43° MayJune: average high 62 °F, low 49 °F 62°49° JunJuly: average high 63 °F, low 52 °F 63°52° JulAugust: average high 62 °F, low 51 °F 62°51° AugSeptember: average high 56 °F, low 46 °F 56°46° SepOctober: average high 48 °F, low 39 °F 48°39° OctNovember: average high 40 °F, low 32 °F 40°32° NovDecember: average high 36 °F, low 29 °F 36°29° Dec

Precipitation by month inches

0″2″4″6″8″10″12″January: 5.88 in precipitation 5.9 JanFebruary: 5.16 in precipitation 5.2 FebMarch: 6.17 in precipitation 6.2 MarApril: 4.76 in precipitation 4.8 AprMay: 5.09 in precipitation 5.1 MayJune: 4.90 in precipitation 4.9 JunJuly: 6.21 in precipitation 6.2 JulAugust: 7.76 in precipitation 7.8 AugSeptember: 12.71 in precipitation 12.7 SepOctober: 12.27 in precipitation 12.3 OctNovember: 8.75 in precipitation 8.8 NovDecember: 9.93 in precipitation 9.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Juneau Dwtn, AK (3 mi away); precipitation: Juneau Dwtn, AK (3 mi away). Daylight is calculated from latitude.

ZIP codes in Juneau

998016a
−10 to −5 °F
998027a
0 to 5 °F
998037a
0 to 5 °F
998117a
0 to 5 °F
998127a
0 to 5 °F
998507a
0 to 5 °F

Alaska planting zones →

Questions about Juneau

What planting zone is Juneau, AK?

Juneau, AK is in USDA hardiness zones 6a to 7a on the 2023 map (6a: −10 to −5 °F; 7a: 0 to 5 °F).

When is the last frost in Juneau, AK?

The median last spring frost is April 20 and the median first fall frost is October 22 (NOAA 1991–2020 normals, Juneau Dwtn station).

When can I plant a garden in Juneau, AK?

Cool-season crops like peas and spinach go in around Mar 9 – Mar 30; tomatoes, peppers, beans and squash after about Apr 27, once frost risk has passed.

What kind of onions grow in Juneau, AK?

Long-day onions: the longest day is 18 h 17 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Juneau, AK get?

About 89.6 inches of precipitation a year (NOAA 1991–2020 normals).