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

Planting zone for 99786 — Ambler, AK

ZIP code 99786 (Ambler, Northwest Arctic County) is in USDA zone 2a: the coldest winter night averages −50 to −45 °F.

Where ZIP 99786 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.

Zone2a−50 to −45 °F

Coldest night−45.6 to −42.8 °C

Last frostrare

First frostrare

2012 zone1a

Was 1a 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 2a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ambler, 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

No NOAA station with frost records lies within 90 miles of Ambler, AK, so we don't show frost dates here rather than guess. Your local extension office can give you a date.

Soil in Ambler, AK

The soil mapped at the center of ZIP 99786 is E43-Arctic scrub-sedge-gravelly frozen till slopes — peat, poorly drained.

TexturePeattop layer

pH4.5strongly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter80%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Western Brooks Range Mountains, Foothills, and Valleys-Boreal Upland and Lowland-Glaciated Valleys.

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 99786; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ambler, AK

Longest day24 h 00 mindaylight on June 21

Shortest day1 h 20 mindaylight on December 21

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

Daylight is calculated from latitude.

Nearby ZIP codes

2 of the 3 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

Alaska planting zones →

Questions about 99786

What planting zone is ZIP code 99786?

ZIP code 99786 (Ambler, AK) is in USDA hardiness zone 2a on the 2023 map: the coldest night of an average winter reaches −50 to −45 °F (−45.6 to −42.8 °C).

What kind of soil does 99786 have?

The USDA soil survey maps E43-Arctic scrub-sedge-gravelly frozen till slopes at the center of ZIP 99786: peat, poorly drained, pH about 4.5 (strongly acidic).

What kind of onions grow in Ambler, AK?

Long-day onions: the longest day near 99786 is 24 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99786 change?

Yes. The 2012 USDA map put 99786 in zone 1a; the 2023 map puts it in zone 2a. The newer map uses 1991–2020 data and more weather stations.