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

Planting zone for 99820 — Angoon, AK

ZIP code 99820 (Angoon, Hoonah-Angoon County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 29 and the first fall frost October 25.

Where ZIP 99820 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 29
First frostOct 25
2012 zone7b

Was 7b on the 2012 map — half a zone colder now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Angoon, 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 Angoon, AK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 29median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 25median — 10% chance by Oct 7
Growing season176 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 10 and returns around November 9.

From the NOAA station Hidden Falls Hatchery, AK — 25 miles away, elevation 23 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 99820

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 18 – Apr 1
SpinachSow outdoors · Mar 18 – Apr 8
Broccoli, cabbageStart indoors · Feb 18 – Mar 4
Broccoli, cabbageTransplant · Apr 8 – Apr 22
Onion setsPlant outdoors · Apr 1 – Apr 15
PotatoesPlant outdoors · Apr 8 – Apr 22
LettuceSow outdoors · Apr 1 – Apr 15
Carrots, beetsSow outdoors · Apr 8 – Apr 22
TomatoesStart indoors · Mar 4 – Mar 18
TomatoesTransplant · May 6 – May 20
Peppers, eggplantStart indoors · Feb 18 – Mar 4
Peppers, eggplantTransplant · May 13 – May 27
BeansSow outdoors · May 6 – May 20
Sweet cornSow outdoors · May 6 – May 20
Cucumbers, squashSow outdoors · May 6 – May 20
Fall lettuce, spinachSow outdoors · Aug 30 – Sep 13
GarlicPlant cloves · Oct 11 – Nov 15
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 25) 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 7a in Alaska

289 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 50

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 125

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 89

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 Angoon, AK.

Soil in Angoon, AK

The soil mapped at the center of ZIP 99820 is E20-maritime forest-loamy colluvial slopes, shallow — moderately decomposed plant material, moderately well drained.

TextureModerately decomposed plant materialtop layer
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter75%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Alexander Archipelago-Gulf of Alaska Coast-Maritime Upland 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 99820; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Angoon, AK

Summer high60 °Faverage high, July
Winter low28 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights120nights a year at 32 °F or less
Growing degree days461base 50 °F — the season’s usable heat
Longest day18 h 00 mindaylight on June 21
Shortest day6 h 37 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation128.1 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°32 °FJanuary: average high 35 °F, low 28 °F 35°28° JanFebruary: average high 36 °F, low 28 °F 36°28° FebMarch: average high 39 °F, low 29 °F 39°29° MarApril: average high 46 °F, low 34 °F 46°34° AprMay: average high 53 °F, low 40 °F 53°40° MayJune: average high 58 °F, low 47 °F 58°47° JunJuly: average high 60 °F, low 50 °F 60°50° JulAugust: average high 60 °F, low 50 °F 60°50° AugSeptember: average high 55 °F, low 46 °F 55°46° SepOctober: average high 47 °F, low 39 °F 47°39° OctNovember: average high 39 °F, low 32 °F 39°32° NovDecember: average high 36 °F, low 30 °F 36°30° Dec

Precipitation by month inches

0″2″4″6″8″10″12″14″16″18″January: 13.57 in precipitation 13.6 JanFebruary: 9.27 in precipitation 9.3 FebMarch: 10.66 in precipitation 10.7 MarApril: 8.11 in precipitation 8.1 AprMay: 4.77 in precipitation 4.8 MayJune: 4.03 in precipitation 4.0 JunJuly: 5.06 in precipitation 5.1 JulAugust: 6.90 in precipitation 6.9 AugSeptember: 12.94 in precipitation 12.9 SepOctober: 15.96 in precipitation 16.0 OctNovember: 18.98 in precipitation 19.0 NovDecember: 17.83 in precipitation 17.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hidden Falls Hatchery, AK (25 mi away); precipitation: Hidden Falls Hatchery, AK (25 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

998357b
Sitka, AK · 41 mi
998307b
Kake, AK · 43 mi
998297a
Hoonah, AK · 59 mi
998247a
Douglas, AK · 61 mi
998027a
Juneau, AK · 64 mi
998037a
Juneau, AK · 64 mi
998117a
Juneau, AK · 64 mi
998127a
Juneau, AK · 66 mi

Alaska planting zones →

Questions about 99820

What planting zone is ZIP code 99820?

ZIP code 99820 (Angoon, AK) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Angoon, AK?

The median last spring frost (32 °F) near 99820 is April 29; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hidden Falls Hatchery station.

When is the first frost in Angoon, AK?

The median first fall frost near 99820 is October 25, giving a median frost-free growing season of 176 days.

When should I plant tomatoes in 99820?

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

How much rain and snow does 99820 get?

About 128.1 inches of precipitation a year (NOAA 1991–2020 normals, Hidden Falls Hatchery station).

How hot do summers get in Angoon, AK?

The average high peaks at 60 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 99820 have?

The USDA soil survey maps E20-maritime forest-loamy colluvial slopes, shallow at the center of ZIP 99820: moderately decomposed plant material, moderately well drained, pH about 5.5 (moderately acidic).

What kind of onions grow in Angoon, AK?

Long-day onions: the longest day near 99820 is 18 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99820 change?

Yes. The 2012 USDA map put 99820 in zone 7b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.