Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 99767 — Rampart, AK

ZIP code 99767 (Rampart, Yukon-Koyukuk (CA) County) is in USDA zone 1b: the coldest winter night averages −55 to −50 °F. The median last spring frost is May 29 and the first fall frost August 28.

Where ZIP 99767 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.

Zone1b−55 to −50 °F

Coldest night−48.3 to −45.6 °C

Last frostMay 29

First frostAug 28

2012 zone1b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 1b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Rampart, 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 Rampart, AK

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 29median — 50% chance of a later frost

Safe for tender plantsJune 16only 10% chance of frost after

First fall frostAugust 28median — 10% chance by Aug 10

Growing season89 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 16 and returns around September 8.

From the NOAA station Tanana Calhoun Mem Airport, AK — 61 miles away, elevation 226 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 99767

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 17 – May 1

SpinachSow outdoors · Apr 17 – May 8

Broccoli, cabbageStart indoors · Mar 20 – Apr 3

Broccoli, cabbageTransplant · May 8 – May 22

Onion setsPlant outdoors · May 1 – May 15

PotatoesPlant outdoors · May 8 – May 22

LettuceSow outdoors · May 1 – May 15

Carrots, beetsSow outdoors · May 8 – May 22

TomatoesStart indoors · Apr 3 – Apr 17

TomatoesTransplant · Jun 5 – Jun 19

Peppers, eggplantStart indoors · Mar 20 – Apr 3

Peppers, eggplantTransplant · Jun 12 – Jun 26

BeansSow outdoors · Jun 5 – Jun 19

Sweet cornSow outdoors · Jun 5 – Jun 19

Cucumbers, squashSow outdoors · Jun 5 – Jun 19

Fall lettuce, spinachSow outdoors · Jul 3 – Jul 17

GarlicPlant cloves · Aug 14 – Sep 18

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 29) and first fall frost (Aug 28) 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 1b in Alaska

37 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −55 °F or colder — the bottom of zone 1b. 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 Rampart, AK.

Soil in Rampart, AK

The soil mapped at the center of ZIP 99767 is Kandik — slightly decomposed plant material, moderately well drained.

TextureSlightly decomposed plant materialtop layer

DrainageModerately well drainednatural drainage class

Organic matter75%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Kandik family-Kandik family, thawed complex.

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 99767; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rampart, AK

Summer high73 °Faverage high, June

Winter low−21 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights252nights a year at 32 °F or less

Growing degree days657base 50 °F — the season’s usable heat

Longest day22 h 54 mindaylight on June 21

Shortest day3 h 12 mindaylight on December 21

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

Precipitation14 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: Manley Hot Springs 15ne, AK (26 mi away); precipitation: Manley Hot Springs 15ne, AK (26 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

997582a

Minto, AK · 33 mi

997741a

Stevens Village, AK · 47 mi

997561b

Manley Hot Springs, AK · 63 mi

Bettles Field, AK · 94 mi

997432a

Healy, AK · 109 mi

Alaska planting zones →

Questions about 99767

What planting zone is ZIP code 99767?

ZIP code 99767 (Rampart, AK) is in USDA hardiness zone 1b on the 2023 map: the coldest night of an average winter reaches −55 to −50 °F (−48.3 to −45.6 °C).

When is the last frost in Rampart, AK?

The median last spring frost (32 °F) near 99767 is May 29; after June 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Tanana Calhoun Mem Airport station.

When is the first frost in Rampart, AK?

The median first fall frost near 99767 is August 28, giving a median frost-free growing season of 89 days.

When should I plant tomatoes in 99767?

Start tomato seeds indoors around Apr 3 – Apr 17 and set transplants outside around Jun 5 – Jun 19, one to three weeks after the median last frost.

How much rain and snow does 99767 get?

About 14 inches of precipitation a year (NOAA 1991–2020 normals, Manley Hot Springs 15ne station).

How hot do summers get in Rampart, AK?

The average high peaks at 73 °F in June, with about 0 days a year at 90 °F or more.

What kind of soil does 99767 have?

The USDA soil survey maps Kandik at the center of ZIP 99767: slightly decomposed plant material, moderately well drained.

What kind of onions grow in Rampart, AK?

Long-day onions: the longest day near 99767 is 22 h 54 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).