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

Planting zone for 83633 — King Hill, ID

ZIP code 83633 (King Hill, Elmore County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 1 and the first fall frost October 3.

Where ZIP 83633 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostMay 1

First frostOct 3

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for King Hill, 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 King Hill, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsMay 16only 10% chance of frost after

First fall frostOctober 3median — 10% chance by Sep 16

Growing season154 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 16.

From the NOAA station Glenns Ferry, ID — 9 miles away, elevation 2,467 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 83633

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 20 – Apr 3

SpinachSow outdoors · Mar 20 – Apr 10

Broccoli, cabbageStart indoors · Feb 20 – Mar 6

Broccoli, cabbageTransplant · Apr 10 – Apr 24

Onion setsPlant outdoors · Apr 3 – Apr 17

PotatoesPlant outdoors · Apr 10 – Apr 24

LettuceSow outdoors · Apr 3 – Apr 17

Carrots, beetsSow outdoors · Apr 10 – Apr 24

TomatoesStart indoors · Mar 6 – Mar 20

TomatoesTransplant · May 8 – May 22

Peppers, eggplantStart indoors · Feb 20 – Mar 6

Peppers, eggplantTransplant · May 15 – May 29

BeansSow outdoors · May 8 – May 22

Sweet cornSow outdoors · May 8 – May 22

Cucumbers, squashSow outdoors · May 8 – May 22

Fall lettuce, spinachSow outdoors · Aug 8 – Aug 22

GarlicPlant cloves · Sep 19 – Oct 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 3) 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 83633 came on Mar 5 — 20 days earlier than the 1991–2020 average (Mar 25).

average
Mar 252026
Mar 5

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 7a in Idaho

575 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 King Hill, ID.

Soil in King Hill, ID

The soil mapped at the center of ZIP 83633 is Chilcott — silty clay, well drained.

TextureSilty clayholds water and nutrients; slow to drain and warm up

pH7.2neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Chilcott-Kunaton-Chardoton complex, 2 to 12 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 83633; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in King Hill, ID

Summer high99 °Faverage high, July

Winter low25 °Faverage low, January

Hot days82days a year at 90 °F or more

Freezing nights144nights a year at 32 °F or less

Growing degree days3,542base 50 °F — the season’s usable heat

Longest day15 h 22 mindaylight on June 21

Shortest day9 h 00 mindaylight on December 21

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

Precipitation11 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: Glenns Ferry, ID (9 mi away); precipitation: Glenns Ferry 1.6 N, ID (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

836237a

Glenns Ferry, ID · 10 mi

833375a

Hill City, ID · 13 mi

Mountain Home, ID · 29 mi

Idaho planting zones →

Questions about 83633

What planting zone is ZIP code 83633?

ZIP code 83633 (King Hill, ID) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in King Hill, ID?

The median last spring frost (32 °F) near 83633 is May 1; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Glenns Ferry station.

When is the first frost in King Hill, ID?

The median first fall frost near 83633 is October 3, giving a median frost-free growing season of 154 days.

When should I plant tomatoes in 83633?

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

How much rain and snow does 83633 get?

About 11 inches of precipitation a year (NOAA 1991–2020 normals, Glenns Ferry 1.6 N station).

How hot do summers get in King Hill, ID?

The average high peaks at 99 °F in July, with about 82 days a year at 90 °F or more.

What kind of soil does 83633 have?

The USDA soil survey maps Chilcott at the center of ZIP 83633: silty clay, well drained, pH about 7.2 (neutral).

Did spring come early in King Hill, ID in 2026?

Spring leaf-out near 83633 came on Mar 5 in 2026, 20 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in King Hill, ID?

Long-day onions: the longest day near 83633 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83633 change?

Yes. The 2012 USDA map put 83633 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.