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

Planting zone for 83540 — Lapwai, ID

ZIP code 83540 (Lapwai, Nez Perce County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is May 23 and the first fall frost September 25.

Where ZIP 83540 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.

Zone7b5 to 10 °F

Coldest night−15 to −12.2 °C

Last frostMay 23

First frostSep 25

2012 zone7b

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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Lapwai, 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 Lapwai, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 23median — 50% chance of a later frost

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

First fall frostSeptember 25median — 10% chance by Sep 7

Growing season121 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 9.

From the NOAA station Winchester, ID — 11 miles away, elevation 3,973 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 83540

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 11 – Apr 25

SpinachSow outdoors · Apr 11 – May 2

Broccoli, cabbageStart indoors · Mar 14 – Mar 28

Broccoli, cabbageTransplant · May 2 – May 16

Onion setsPlant outdoors · Apr 25 – May 9

PotatoesPlant outdoors · May 2 – May 16

LettuceSow outdoors · Apr 25 – May 9

Carrots, beetsSow outdoors · May 2 – May 16

TomatoesStart indoors · Mar 28 – Apr 11

TomatoesTransplant · May 30 – Jun 13

Peppers, eggplantStart indoors · Mar 14 – Mar 28

Peppers, eggplantTransplant · Jun 6 – Jun 20

BeansSow outdoors · May 30 – Jun 13

Sweet cornSow outdoors · May 30 – Jun 13

Cucumbers, squashSow outdoors · May 30 – Jun 13

Fall lettuce, spinachSow outdoors · Jul 31 – Aug 14

GarlicPlant cloves · Sep 11 – Oct 16

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 23) and first fall frost (Sep 25) 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 83540 came on Mar 17 — 5 days earlier than the 1991–2020 average (Mar 22).

average
Mar 222026
Mar 17

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 7b in Idaho

575 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 7b. 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 Lapwai, ID.

Soil in Lapwai, ID

The soil mapped at the center of ZIP 83540 is Naff — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Naff-Waha complex, 12 to 25 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 83540; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lapwai, ID

Summer high79 °Faverage high, August

Winter low22 °Faverage low, December

Hot days5days a year at 90 °F or more

Freezing nights171nights a year at 32 °F or less

Growing degree days1,369base 50 °F — the season’s usable heat

Longest day15 h 48 mindaylight on June 21

Shortest day8 h 36 mindaylight on December 21

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

Precipitation21.8 inper year, rain and melted snow

Snowfall87 inper year; 90 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: Winchester, ID (11 mi away); precipitation: Winchester, ID (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Juliaetta, ID · 13 mi

Winchester, ID · 19 mi

991797a

Uniontown, WA · 19 mi

Idaho planting zones →

Questions about 83540

What planting zone is ZIP code 83540?

ZIP code 83540 (Lapwai, ID) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Lapwai, ID?

The median last spring frost (32 °F) near 83540 is May 23; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Winchester station.

When is the first frost in Lapwai, ID?

The median first fall frost near 83540 is September 25, giving a median frost-free growing season of 121 days.

When should I plant tomatoes in 83540?

Start tomato seeds indoors around Mar 28 – Apr 11 and set transplants outside around May 30 – Jun 13, one to three weeks after the median last frost.

How much rain and snow does 83540 get?

About 21.8 inches of precipitation a year and 87 inches of snowfall (NOAA 1991–2020 normals, Winchester station).

How hot do summers get in Lapwai, ID?

The average high peaks at 79 °F in August, with about 5 days a year at 90 °F or more.

What kind of soil does 83540 have?

The USDA soil survey maps Naff at the center of ZIP 83540: silt loam, well drained, pH about 6.7 (neutral).

Did spring come early in Lapwai, ID in 2026?

Spring leaf-out near 83540 came on Mar 17 in 2026, 5 days earlier than the 1991–2020 average (Mar 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lapwai, ID?

Long-day onions: the longest day near 83540 is 15 h 48 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).