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

Planting zone for 83602 — Banks, ID

ZIP code 83602 (Banks, Boise County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is June 1 and the first fall frost September 10.

Where ZIP 83602 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 frostJun 1

First frostSep 10

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 Banks, 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 Banks, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsJune 20only 10% chance of frost after

First fall frostSeptember 10median — 10% chance by Aug 28

Growing season102 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 11 and returns around September 24.

From the NOAA station Garden Valley, ID — 9 miles away, elevation 3,101 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 83602

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

Fall lettuce, spinachSow outdoors · Jul 16 – Jul 30

GarlicPlant cloves · Aug 27 – Oct 1

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 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 83602 came on Mar 19 — 24 days earlier than the 1991–2020 average (Apr 12).

average
Apr 122026
Mar 19

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 Banks, ID.

Soil in Banks, ID

The soil mapped at the center of ZIP 83602 is Drybuck — 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 matter95%high

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Drybuck-Whisk complex, 8 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 83602; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Banks, ID

Summer high89 °Faverage high, July

Winter low19 °Faverage low, January

Hot days46days a year at 90 °F or more

Freezing nights180nights a year at 32 °F or less

Growing degree days1,953base 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)

Precipitation26.6 inper year, rain and melted snow

Snowfall69 inper year; 94 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: Garden Valley, ID (9 mi away); precipitation: Garden Valley, ID (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

836707a

Sweet, ID · 10 mi

836666b

Placerville, ID · 12 mi

836297a

Horseshoe Bend, ID · 12 mi

836577a

Ola, ID · 13 mi

836226b

Garden Valley, ID · 13 mi

836177a

Emmett, ID · 21 mi

836316b

Idaho City, ID · 23 mi

836167a

Eagle, ID · 25 mi

Idaho planting zones →

Questions about 83602

What planting zone is ZIP code 83602?

ZIP code 83602 (Banks, 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 Banks, ID?

The median last spring frost (32 °F) near 83602 is June 1; after June 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Garden Valley station.

When is the first frost in Banks, ID?

The median first fall frost near 83602 is September 10, giving a median frost-free growing season of 102 days.

When should I plant tomatoes in 83602?

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

How much rain and snow does 83602 get?

About 26.6 inches of precipitation a year and 69 inches of snowfall (NOAA 1991–2020 normals, Garden Valley station).

How hot do summers get in Banks, ID?

The average high peaks at 89 °F in July, with about 46 days a year at 90 °F or more.

What kind of soil does 83602 have?

The USDA soil survey maps Drybuck at the center of ZIP 83602: slightly decomposed plant material, somewhat excessively drained, pH about 5.0 (strongly acidic).

Did spring come early in Banks, ID in 2026?

Spring leaf-out near 83602 came on Mar 19 in 2026, 24 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Banks, ID?

Long-day onions: the longest day near 83602 is 15 h 30 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83602 change?

Yes. The 2012 USDA map put 83602 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.