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

Planting zone for 83637 — Lowman, ID

ZIP code 83637 (Lowman, Boise County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is June 6 and the first fall frost September 4.

Where ZIP 83637 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 6

First frostSep 4

2012 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Lowman, 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 Lowman, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 6median — 50% chance of a later frost

Safe for tender plantsJuly 1only 10% chance of frost after

First fall frostSeptember 4median — 10% chance by Aug 19

Growing season87 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 15 and returns around September 23.

From the NOAA station Lowman, ID — 23 miles away, elevation 3,921 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 83637

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 25 – May 9

SpinachSow outdoors · Apr 25 – May 16

Broccoli, cabbageStart indoors · Mar 28 – Apr 11

Broccoli, cabbageTransplant · May 16 – May 30

Onion setsPlant outdoors · May 9 – May 23

PotatoesPlant outdoors · May 16 – May 30

LettuceSow outdoors · May 9 – May 23

Carrots, beetsSow outdoors · May 16 – May 30

TomatoesStart indoors · Apr 11 – Apr 25

TomatoesTransplant · Jun 13 – Jun 27

Peppers, eggplantStart indoors · Mar 28 – Apr 11

Peppers, eggplantTransplant · Jun 20 – Jul 4

BeansSow outdoors · Jun 13 – Jun 27

Sweet cornSow outdoors · Jun 13 – Jun 27

Cucumbers, squashSow outdoors · Jun 13 – Jun 27

Fall lettuce, spinachSow outdoors · Jul 10 – Jul 24

GarlicPlant cloves · Aug 21 – Sep 25

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 6) and first fall frost (Sep 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 83637 came on Apr 23 — 13 days earlier than the 1991–2020 average (May 6).

average
May 62026
Apr 23

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 Lowman, ID.

Soil in Lowman, ID

The soil mapped at the center of ZIP 83637 is Typic Argixerolls family — gravelly sandy loam, well drained.

TextureGravelly sandy loamdrains and warms fast; dries out and needs more feeding

pH6.4slightly acidic; 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: Typic Argixerolls and Pachic Haploxerolls soils, 30 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 83637; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lowman, ID

Summer high80 °Faverage high, July

Winter low4 °Faverage low, January

Hot days3days a year at 90 °F or more

Freezing nights279nights a year at 32 °F or less

Growing degree days777base 50 °F — the season’s usable heat

Longest day15 h 30 mindaylight on June 21

Shortest day8 h 52 mindaylight on December 21

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

Precipitation31 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: Stanley Rs, ID (12 mi away); precipitation: Graham Guard Sta., ID (12 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.

Idaho City, ID · 34 mi

836226b

Garden Valley, ID · 36 mi

833405b

Ketchum, ID · 38 mi

836666b

Placerville, ID · 42 mi

833276a

Fairfield, ID · 46 mi

Idaho planting zones →

Questions about 83637

What planting zone is ZIP code 83637?

ZIP code 83637 (Lowman, 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 Lowman, ID?

The median last spring frost (32 °F) near 83637 is June 6; after July 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lowman station.

When is the first frost in Lowman, ID?

The median first fall frost near 83637 is September 4, giving a median frost-free growing season of 87 days.

When should I plant tomatoes in 83637?

Start tomato seeds indoors around Apr 11 – Apr 25 and set transplants outside around Jun 13 – Jun 27, one to three weeks after the median last frost.

How much rain and snow does 83637 get?

About 31 inches of precipitation a year (NOAA 1991–2020 normals, Graham Guard Sta. station).

How hot do summers get in Lowman, ID?

The average high peaks at 80 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 83637 have?

The USDA soil survey maps Typic Argixerolls family at the center of ZIP 83637: gravelly sandy loam, well drained, pH about 6.4 (slightly acidic).

Did spring come early in Lowman, ID in 2026?

Spring leaf-out near 83637 came on Apr 23 in 2026, 13 days earlier than the 1991–2020 average (May 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lowman, ID?

Long-day onions: the longest day near 83637 is 15 h 30 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).