Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 83466 — North Fork, ID

ZIP code 83466 (North Fork, Lemhi County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is June 1 and the first fall frost September 17.

Where ZIP 83466 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostJun 1

First frostSep 17

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for North Fork, ID…

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 North Fork, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 1median — 50% chance of a later frost

Safe for tender plantsJune 19only 10% chance of frost after

First fall frostSeptember 17median — 10% chance by Sep 2

Growing season107 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 10 and returns around September 30.

From the NOAA station Gibbonsville #2, ID — 11 miles away, elevation 4,482 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 83466

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

Fall lettuce, spinachSow outdoors · Jul 23 – Aug 6

GarlicPlant cloves · Sep 3 – Oct 8

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 17) 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.

When spring arrived in 2026

In 2026, spring leaf-out near 83466 came on Apr 10 — 12 days earlier than the 1991–2020 average (Apr 22).

average
Apr 222026
Apr 10

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 6a in Idaho

567 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 North Fork, ID.

Soil in North Fork, ID

The soil mapped at the center of ZIP 83466 is Ustic Haplocryalfs family — 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 matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Ustic Haplocryalfs family, extremely stony surface-Worock family-Ustic Haplocryepts family, very stony surface, complex, 25 to 70 percent slopes.

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 83466; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in North Fork, ID

Summer high83 °Faverage high, July

Winter low11 °Faverage low, January

Hot days11days a year at 90 °F or more

Freezing nights217nights a year at 32 °F or less

Growing degree days1,411base 50 °F — the season’s usable heat

Longest day15 h 40 mindaylight on June 21

Shortest day8 h 43 mindaylight on December 21

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

Precipitation31.6 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: Gibbonsville #2, ID (11 mi away); precipitation: Moose Creek, ID (18 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

834635b

Gibbonsville, ID · 11 mi

Idaho planting zones →

Questions about 83466

What planting zone is ZIP code 83466?

ZIP code 83466 (North Fork, ID) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in North Fork, ID?

The median last spring frost (32 °F) near 83466 is June 1; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Gibbonsville #2 station.

When is the first frost in North Fork, ID?

The median first fall frost near 83466 is September 17, giving a median frost-free growing season of 107 days.

When should I plant tomatoes in 83466?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 83466 get?

About 31.6 inches of precipitation a year (NOAA 1991–2020 normals, Moose Creek station).

How hot do summers get in North Fork, ID?

The average high peaks at 83 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 83466 have?

The USDA soil survey maps Ustic Haplocryalfs family at the center of ZIP 83466: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in North Fork, ID in 2026?

Spring leaf-out near 83466 came on Apr 10 in 2026, 12 days earlier than the 1991–2020 average (Apr 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in North Fork, ID?

Long-day onions: the longest day near 83466 is 15 h 40 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83466 change?

Yes. The 2012 USDA map put 83466 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.