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

Planting zone for 83830 — Fernwood, ID

ZIP code 83830 (Fernwood, Benewah County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 3 and the first fall frost October 4.

Where ZIP 83830 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 3

First frostOct 4

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Fernwood, 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 Fernwood, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 3median — 50% chance of a later frost

Safe for tender plantsMay 18only 10% chance of frost after

First fall frostOctober 4median — 10% chance by Sep 18

Growing season152 daysfrost-free, median

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

From the NOAA station Saint Maries, ID — 19 miles away, elevation 2,152 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 83830

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 22 – Apr 5

SpinachSow outdoors · Mar 22 – Apr 12

Broccoli, cabbageStart indoors · Feb 22 – Mar 8

Broccoli, cabbageTransplant · Apr 12 – Apr 26

Onion setsPlant outdoors · Apr 5 – Apr 19

PotatoesPlant outdoors · Apr 12 – Apr 26

LettuceSow outdoors · Apr 5 – Apr 19

Carrots, beetsSow outdoors · Apr 12 – Apr 26

TomatoesStart indoors · Mar 8 – Mar 22

TomatoesTransplant · May 10 – May 24

Peppers, eggplantStart indoors · Feb 22 – Mar 8

Peppers, eggplantTransplant · May 17 – May 31

BeansSow outdoors · May 10 – May 24

Sweet cornSow outdoors · May 10 – May 24

Cucumbers, squashSow outdoors · May 10 – May 24

Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23

GarlicPlant cloves · Sep 20 – Oct 25

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 4) 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 83830 came on Apr 9 — 9 days earlier than the 1991–2020 average (Apr 18).

average
Apr 182026
Apr 9

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 Fernwood, ID.

Soil in Fernwood, ID

The soil mapped at the center of ZIP 83830 is Reggear — slightly decomposed plant material, moderately well drained.

TextureSlightly decomposed plant materialtop layer

pH6.5neutral; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter75%high

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Reggear silt loam, 3 to 20 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 83830; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Fernwood, ID

Summer high85 °Faverage high, August

Winter low24 °Faverage low, January

Hot days20days a year at 90 °F or more

Freezing nights138nights a year at 32 °F or less

Growing degree days1,995base 50 °F — the season’s usable heat

Longest day15 h 54 mindaylight on June 21

Shortest day8 h 30 mindaylight on December 21

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

Precipitation56.1 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: Saint Maries, ID (19 mi away); precipitation: Mica Creek, ID (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Saint Maries, ID · 16 mi

Elk River, ID · 22 mi

Idaho planting zones →

Questions about 83830

What planting zone is ZIP code 83830?

ZIP code 83830 (Fernwood, 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 Fernwood, ID?

The median last spring frost (32 °F) near 83830 is May 3; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Saint Maries station.

When is the first frost in Fernwood, ID?

The median first fall frost near 83830 is October 4, giving a median frost-free growing season of 152 days.

When should I plant tomatoes in 83830?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 83830 get?

About 56.1 inches of precipitation a year (NOAA 1991–2020 normals, Mica Creek station).

How hot do summers get in Fernwood, ID?

The average high peaks at 85 °F in August, with about 20 days a year at 90 °F or more.

What kind of soil does 83830 have?

The USDA soil survey maps Reggear at the center of ZIP 83830: slightly decomposed plant material, moderately well drained, pH about 6.5 (neutral).

Did spring come early in Fernwood, ID in 2026?

Spring leaf-out near 83830 came on Apr 9 in 2026, 9 days earlier than the 1991–2020 average (Apr 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Fernwood, ID?

Long-day onions: the longest day near 83830 is 15 h 54 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83830 change?

Yes. The 2012 USDA map put 83830 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.