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

Planting zone for 83336 — Heyburn, ID

ZIP code 83336 (Heyburn, Minidoka County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 7 and the first fall frost October 4.

Where ZIP 83336 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostMay 7

First frostOct 4

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Heyburn, 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 Heyburn, ID

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 7median — 50% chance of a later frost

Safe for tender plantsMay 23only 10% chance of frost after

First fall frostOctober 4median — 10% chance by Sep 21

Growing season150 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 17.

From the NOAA station Burley Municipal Airport, ID — 3 miles away, elevation 4,144 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 83336

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 26 – Apr 9

SpinachSow outdoors · Mar 26 – Apr 16

Broccoli, cabbageStart indoors · Feb 26 – Mar 12

Broccoli, cabbageTransplant · Apr 16 – Apr 30

Onion setsPlant outdoors · Apr 9 – Apr 23

PotatoesPlant outdoors · Apr 16 – Apr 30

LettuceSow outdoors · Apr 9 – Apr 23

Carrots, beetsSow outdoors · Apr 16 – Apr 30

TomatoesStart indoors · Mar 12 – Mar 26

TomatoesTransplant · May 14 – May 28

Peppers, eggplantStart indoors · Feb 26 – Mar 12

Peppers, eggplantTransplant · May 21 – Jun 4

BeansSow outdoors · May 14 – May 28

Sweet cornSow outdoors · May 14 – May 28

Cucumbers, squashSow outdoors · May 14 – May 28

Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23

GarlicPlant cloves · Sep 20 – Oct 25

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 7) and first fall frost (Oct 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 83336 came on Mar 17 — 16 days earlier than the 1991–2020 average (Apr 2).

average
Apr 22026
Mar 17

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 6b in Idaho

570 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Heyburn, ID.

Soil in Heyburn, ID

The soil mapped at the center of ZIP 83336 is Paulmyers — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables

pH7.9alkaline; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if irrigated and reclaimed of excess salts and sodiumUSDA classification

Map unit: Paulmyers loam, 0 to 2 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 83336; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Heyburn, ID

Summer high88 °Faverage high, July

Winter low21 °Faverage low, January

Hot days33days a year at 90 °F or more

Freezing nights146nights a year at 32 °F or less

Growing degree days2,381base 50 °F — the season’s usable heat

Longest day15 h 19 mindaylight on June 21

Shortest day9 h 03 mindaylight on December 21

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

Precipitation10.3 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: Burley Municipal Airport, ID (3 mi away); precipitation: Burley Municipal Airport, ID (3 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.

Idaho planting zones →

Questions about 83336

What planting zone is ZIP code 83336?

ZIP code 83336 (Heyburn, ID) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Heyburn, ID?

The median last spring frost (32 °F) near 83336 is May 7; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Burley Municipal Airport station.

When is the first frost in Heyburn, ID?

The median first fall frost near 83336 is October 4, giving a median frost-free growing season of 150 days.

When should I plant tomatoes in 83336?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 83336 get?

About 10.3 inches of precipitation a year (NOAA 1991–2020 normals, Burley Municipal Airport station).

How hot do summers get in Heyburn, ID?

The average high peaks at 88 °F in July, with about 33 days a year at 90 °F or more.

What kind of soil does 83336 have?

The USDA soil survey maps Paulmyers at the center of ZIP 83336: loam, somewhat poorly drained, pH about 7.9 (alkaline).

Did spring come early in Heyburn, ID in 2026?

Spring leaf-out near 83336 came on Mar 17 in 2026, 16 days earlier than the 1991–2020 average (Apr 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Heyburn, ID?

Long-day onions: the longest day near 83336 is 15 h 19 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83336 change?

Yes. The 2012 USDA map put 83336 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.