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

Planting zone for 99652 — Big Lake, AK

ZIP code 99652 (Big Lake, Matanuska-Susitna Borough) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 29 and the first fall frost September 7.

Where ZIP 99652 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.

Zone4a−30 to −25 °F

Coldest night−34.4 to −31.7 °C

Last frostMay 29

First frostSep 7

2012 zone3b

Was 3b 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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Big Lake, 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 Big Lake, 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 9only 10% chance of frost after

First fall frostSeptember 7median — 10% chance by Aug 24

Growing season100 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 14 and returns around September 19.

From the NOAA station Whites Crossing, AK — 13 miles away, elevation 269 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 99652

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 13 – Jul 27

GarlicPlant cloves · Aug 24 – Sep 28

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 29) and first fall frost (Sep 7) 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 4a in Alaska

240 plants native to Alaska, recorded in Alaska, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. 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 Big Lake, AK.

Soil in Big Lake, AK

The soil mapped at the center of ZIP 99652 is Kichatna — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter60%high

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Kichatna silt loam, sloping and moderately steep.

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 99652; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Big Lake, AK

Summer high71 °Faverage high, July

Winter low−2 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights228nights a year at 32 °F or less

Growing degree days794base 50 °F — the season’s usable heat

Longest day19 h 31 mindaylight on June 21

Shortest day5 h 20 mindaylight on December 21

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

Precipitation17.7 inper year, rain and melted snow

Snowfall71 inper year; 158 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: Whites Crossing, AK (13 mi away); precipitation: Eagle Rvr Gakona Circle, AK (20 mi away). 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.

Anchorage, AK · 21 mi

Alaska planting zones →

Questions about 99652

What planting zone is ZIP code 99652?

ZIP code 99652 (Big Lake, AK) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Big Lake, AK?

The median last spring frost (32 °F) near 99652 is May 29; after June 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Whites Crossing station.

When is the first frost in Big Lake, AK?

The median first fall frost near 99652 is September 7, giving a median frost-free growing season of 100 days.

When should I plant tomatoes in 99652?

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 99652 get?

About 17.7 inches of precipitation a year and 71 inches of snowfall (NOAA 1991–2020 normals, Eagle Rvr Gakona Circle station).

How hot do summers get in Big Lake, 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 99652 have?

The USDA soil survey maps Kichatna at the center of ZIP 99652: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

What kind of onions grow in Big Lake, AK?

Long-day onions: the longest day near 99652 is 19 h 31 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99652 change?

Yes. The 2012 USDA map put 99652 in zone 3b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.