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

Planting zone for 83615 — Donnelly, ID

ZIP code 83615 (Donnelly, Valley County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 30 and the first fall frost September 19.

Where ZIP 83615 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 30

First frostSep 19

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 Donnelly, 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 Donnelly, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 30median — 50% chance of a later frost

Safe for tender plantsJune 21only 10% chance of frost after

First fall frostSeptember 19median — 10% chance by Sep 3

Growing season110 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 6 and returns around October 2.

From the NOAA station Cascade 1 Nw, ID — 12 miles away, elevation 4,895 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 83615

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 18 – May 2

SpinachSow outdoors · Apr 18 – May 9

Broccoli, cabbageStart indoors · Mar 21 – Apr 4

Broccoli, cabbageTransplant · May 9 – May 23

Onion setsPlant outdoors · May 2 – May 16

PotatoesPlant outdoors · May 9 – May 23

LettuceSow outdoors · May 2 – May 16

Carrots, beetsSow outdoors · May 9 – May 23

TomatoesStart indoors · Apr 4 – Apr 18

TomatoesTransplant · Jun 6 – Jun 20

Peppers, eggplantStart indoors · Mar 21 – Apr 4

Peppers, eggplantTransplant · Jun 13 – Jun 27

BeansSow outdoors · Jun 6 – Jun 20

Sweet cornSow outdoors · Jun 6 – Jun 20

Cucumbers, squashSow outdoors · Jun 6 – Jun 20

Fall lettuce, spinachSow outdoors · Jul 25 – Aug 8

GarlicPlant cloves · Sep 5 – Oct 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 30) and first fall frost (Sep 19) 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 83615 came on Apr 15 — 13 days earlier than the 1991–2020 average (Apr 28).

average
Apr 282026
Apr 15

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 Donnelly, ID.

Soil in Donnelly, ID

The soil mapped at the center of ZIP 83615 is Kangas — fine gravelly loamy coarse sand, somewhat excessively drained.

TextureFine gravelly loamy coarse sanddrains and warms fast; dries out and needs more feeding

pH6.3slightly acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter3%moderate

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Kangas fine gravelly loamy coarse sand.

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 83615; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Donnelly, ID

Summer high82 °Faverage high, July

Winter low15 °Faverage low, January

Hot days9days a year at 90 °F or more

Freezing nights225nights a year at 32 °F or less

Growing degree days1,489base 50 °F — the season’s usable heat

Longest day15 h 35 mindaylight on June 21

Shortest day8 h 48 mindaylight on December 21

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

Precipitation25.6 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: Cascade 1 Nw, ID (12 mi away); precipitation: Long Valley, ID (6 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.

Indian Valley, ID · 22 mi

New Meadows, ID · 38 mi

Idaho planting zones →

Questions about 83615

What planting zone is ZIP code 83615?

ZIP code 83615 (Donnelly, 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 Donnelly, ID?

The median last spring frost (32 °F) near 83615 is May 30; after June 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cascade 1 Nw station.

When is the first frost in Donnelly, ID?

The median first fall frost near 83615 is September 19, giving a median frost-free growing season of 110 days.

When should I plant tomatoes in 83615?

Start tomato seeds indoors around Apr 4 – Apr 18 and set transplants outside around Jun 6 – Jun 20, one to three weeks after the median last frost.

How much rain and snow does 83615 get?

About 25.6 inches of precipitation a year (NOAA 1991–2020 normals, Long Valley station).

How hot do summers get in Donnelly, ID?

The average high peaks at 82 °F in July, with about 9 days a year at 90 °F or more.

What kind of soil does 83615 have?

The USDA soil survey maps Kangas at the center of ZIP 83615: fine gravelly loamy coarse sand, somewhat excessively drained, pH about 6.3 (slightly acidic).

Did spring come early in Donnelly, ID in 2026?

Spring leaf-out near 83615 came on Apr 15 in 2026, 13 days earlier than the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Donnelly, ID?

Long-day onions: the longest day near 83615 is 15 h 35 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).