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

Planting zone for 83801 — Athol, ID

ZIP code 83801 (Athol, Kootenai County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 22 and the first fall frost September 22.

Where ZIP 83801 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostMay 22

First frostSep 22

2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Athol, 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 Athol, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 22median — 50% chance of a later frost

Safe for tender plantsJune 6only 10% chance of frost after

First fall frostSeptember 22median — 10% chance by Sep 3

Growing season122 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 4 and returns around October 4.

From the NOAA station Bayview Model Basin, ID — 4 miles away, elevation 2,087 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 83801

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 10 – Apr 24

SpinachSow outdoors · Apr 10 – May 1

Broccoli, cabbageStart indoors · Mar 13 – Mar 27

Broccoli, cabbageTransplant · May 1 – May 15

Onion setsPlant outdoors · Apr 24 – May 8

PotatoesPlant outdoors · May 1 – May 15

LettuceSow outdoors · Apr 24 – May 8

Carrots, beetsSow outdoors · May 1 – May 15

TomatoesStart indoors · Mar 27 – Apr 10

TomatoesTransplant · May 29 – Jun 12

Peppers, eggplantStart indoors · Mar 13 – Mar 27

Peppers, eggplantTransplant · Jun 5 – Jun 19

BeansSow outdoors · May 29 – Jun 12

Sweet cornSow outdoors · May 29 – Jun 12

Cucumbers, squashSow outdoors · May 29 – Jun 12

Fall lettuce, spinachSow outdoors · Jul 28 – Aug 11

GarlicPlant cloves · Sep 8 – Oct 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 22) and first fall frost (Sep 22) 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 83801 came on Apr 4 — 12 days earlier than the 1991–2020 average (Apr 16).

average
Apr 162026
Apr 4

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 6b in Idaho

570 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Athol, ID.

Soil in Athol, ID

The soil mapped at the center of ZIP 83801 is Bonner — 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 classprime farmlandUSDA classification

Map unit: Bonner ashy silt loam, 0 to 8 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 83801; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Athol, ID

Summer high80 °Faverage high, July

Winter low22 °Faverage low, December

Hot days9days a year at 90 °F or more

Freezing nights172nights a year at 32 °F or less

Growing degree days1,479base 50 °F — the season’s usable heat

Longest day16 h 02 mindaylight on June 21

Shortest day8 h 22 mindaylight on December 21

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

Precipitation29.8 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: Bayview Model Basin, ID (4 mi away); precipitation: Athol 1.5 Ene, ID (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

838096b

Careywood, ID · 8 mi

838136b

Cocolalla, ID · 11 mi

838356b

Hayden, ID · 11 mi

838696b

Spirit Lake, ID · 12 mi

Blanchard, ID · 16 mi

Idaho planting zones →

Questions about 83801

What planting zone is ZIP code 83801?

ZIP code 83801 (Athol, ID) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Athol, ID?

The median last spring frost (32 °F) near 83801 is May 22; after June 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Bayview Model Basin station.

When is the first frost in Athol, ID?

The median first fall frost near 83801 is September 22, giving a median frost-free growing season of 122 days.

When should I plant tomatoes in 83801?

Start tomato seeds indoors around Mar 27 – Apr 10 and set transplants outside around May 29 – Jun 12, one to three weeks after the median last frost.

How much rain and snow does 83801 get?

About 29.8 inches of precipitation a year (NOAA 1991–2020 normals, Athol 1.5 Ene station).

How hot do summers get in Athol, ID?

The average high peaks at 80 °F in July, with about 9 days a year at 90 °F or more.

What kind of soil does 83801 have?

The USDA soil survey maps Bonner at the center of ZIP 83801: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Athol, ID in 2026?

Spring leaf-out near 83801 came on Apr 4 in 2026, 12 days earlier than the 1991–2020 average (Apr 16), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Athol, ID?

Long-day onions: the longest day near 83801 is 16 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).