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

Planting zone for 83611 — Cascade, ID

ZIP code 83611 (Cascade, Valley County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 2 and the first fall frost October 10.

Where ZIP 83611 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostMay 2

First frostOct 10

2012 zone5a

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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cascade, 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 Cascade, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 2median — 50% chance of a later frost

Safe for tender plantsMay 14only 10% chance of frost after

First fall frostOctober 10median — 10% chance by Sep 26

Growing season159 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 14 and returns around October 23.

From the NOAA station Yellowpine Bar, ID — 17 miles away, elevation 2,480 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 83611

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 21 – Apr 4

SpinachSow outdoors · Mar 21 – Apr 11

Broccoli, cabbageStart indoors · Feb 21 – Mar 7

Broccoli, cabbageTransplant · Apr 11 – Apr 25

Onion setsPlant outdoors · Apr 4 – Apr 18

PotatoesPlant outdoors · Apr 11 – Apr 25

LettuceSow outdoors · Apr 4 – Apr 18

Carrots, beetsSow outdoors · Apr 11 – Apr 25

TomatoesStart indoors · Mar 7 – Mar 21

TomatoesTransplant · May 9 – May 23

Peppers, eggplantStart indoors · Feb 21 – Mar 7

Peppers, eggplantTransplant · May 16 – May 30

BeansSow outdoors · May 9 – May 23

Sweet cornSow outdoors · May 9 – May 23

Cucumbers, squashSow outdoors · May 9 – May 23

Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29

GarlicPlant cloves · Sep 26 – Oct 31

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 10) 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 83611 came on May 1 — 8 days earlier than the 1991–2020 average (May 9).

average
May 92026
May 1

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 5a in Idaho

536 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 Cascade, ID.

Soil in Cascade, ID

The soil mapped at the center of ZIP 83611 is Vitrandic Humixerepts family — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Vitrandic Humixerepts family deep-Vitrandic Humixerepts family complex, 25 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 83611; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cascade, ID

Summer high92 °Faverage high, July

Winter low21 °Faverage low, January

Hot days54days a year at 90 °F or more

Freezing nights160nights a year at 32 °F or less

Growing degree days2,547base 50 °F — the season’s usable heat

Longest day15 h 40 mindaylight on June 21

Shortest day8 h 43 mindaylight on December 21

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

Precipitation21.9 inper year, rain and melted snow

Snowfall45 inper year; 89 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: Yellowpine Bar, ID (17 mi away); precipitation: Yellowpine Bar, ID (17 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

836775a

Yellow Pine, ID · 23 mi

North Fork, ID · 50 mi

598295b

Darby, MT · 51 mi

Idaho planting zones →

Questions about 83611

What planting zone is ZIP code 83611?

ZIP code 83611 (Cascade, ID) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Cascade, ID?

The median last spring frost (32 °F) near 83611 is May 2; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Yellowpine Bar station.

When is the first frost in Cascade, ID?

The median first fall frost near 83611 is October 10, giving a median frost-free growing season of 159 days.

When should I plant tomatoes in 83611?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 83611 get?

About 21.9 inches of precipitation a year and 45 inches of snowfall (NOAA 1991–2020 normals, Yellowpine Bar station).

How hot do summers get in Cascade, ID?

The average high peaks at 92 °F in July, with about 54 days a year at 90 °F or more.

What kind of soil does 83611 have?

The USDA soil survey maps Vitrandic Humixerepts family at the center of ZIP 83611: slightly decomposed plant material, somewhat excessively drained, pH about 5.0 (strongly acidic).

Did spring come early in Cascade, ID in 2026?

Spring leaf-out near 83611 came on May 1 in 2026, 8 days earlier than the 1991–2020 average (May 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cascade, ID?

Long-day onions: the longest day near 83611 is 15 h 40 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).