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

Planting zone for 83414 — Alta, WY

ZIP code 83414 (Alta, Teton County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 14 and the first fall frost September 11.

Where ZIP 83414 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 frostJun 14

First frostSep 11

2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Alta, WY…

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 Alta, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 14median — 50% chance of a later frost

Safe for tender plantsJuly 4only 10% chance of frost after

First fall frostSeptember 11median — 10% chance by Aug 28

Growing season85 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 24 and returns around September 23.

From the NOAA station Alta 1 Nnw, WY — 8 miles away, elevation 6,441 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 83414

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · May 3 – May 17

SpinachSow outdoors · May 3 – May 24

Broccoli, cabbageStart indoors · Apr 5 – Apr 19

Broccoli, cabbageTransplant · May 24 – Jun 7

Onion setsPlant outdoors · May 17 – May 31

PotatoesPlant outdoors · May 24 – Jun 7

LettuceSow outdoors · May 17 – May 31

Carrots, beetsSow outdoors · May 24 – Jun 7

TomatoesStart indoors · Apr 19 – May 3

TomatoesTransplant · Jun 21 – Jul 5

Peppers, eggplantStart indoors · Apr 5 – Apr 19

Peppers, eggplantTransplant · Jun 28 – Jul 12

BeansSow outdoors · Jun 21 – Jul 5

Sweet cornSow outdoors · Jun 21 – Jul 5

Cucumbers, squashSow outdoors · Jun 21 – Jul 5

Fall lettuce, spinachSow outdoors · Jul 17 – Jul 31

GarlicPlant cloves · Aug 28 – Oct 2

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 14) and first fall frost (Sep 11) 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 83414 came on May 4 — 13 days earlier than the 1991–2020 average (May 17).

average
May 172026
May 4

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 Wyoming

542 plants native to the lower 48 states, recorded in Wyoming, 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 Alta, WY.

Soil in Alta, WY

The soil mapped at the center of ZIP 83414 is Koffgo — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH6.5neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Koffgo gravelly ashy loam, 30 to 60 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 83414; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alta, WY

Summer high79 °Faverage high, July

Winter low12 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights204nights a year at 32 °F or less

Growing degree days1,309base 50 °F — the season’s usable heat

Longest day15 h 28 mindaylight on June 21

Shortest day8 h 54 mindaylight on December 21

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

Precipitation49.7 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: Alta 1 Nnw, WY (8 mi away); precipitation: Grand Targhee, WY (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Teton Village, WY · 19 mi

Wyoming planting zones →

Questions about 83414

What planting zone is ZIP code 83414?

ZIP code 83414 (Alta, WY) 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 Alta, WY?

The median last spring frost (32 °F) near 83414 is June 14; after July 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alta 1 Nnw station.

When is the first frost in Alta, WY?

The median first fall frost near 83414 is September 11, giving a median frost-free growing season of 85 days.

When should I plant tomatoes in 83414?

Start tomato seeds indoors around Apr 19 – May 3 and set transplants outside around Jun 21 – Jul 5, one to three weeks after the median last frost.

How much rain and snow does 83414 get?

About 49.7 inches of precipitation a year (NOAA 1991–2020 normals, Grand Targhee station).

How hot do summers get in Alta, WY?

The average high peaks at 79 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 83414 have?

The USDA soil survey maps Koffgo at the center of ZIP 83414: slightly decomposed plant material, well drained, pH about 6.5 (neutral).

Did spring come early in Alta, WY in 2026?

Spring leaf-out near 83414 came on May 4 in 2026, 13 days earlier than the 1991–2020 average (May 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alta, WY?

Long-day onions: the longest day near 83414 is 15 h 28 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83414 change?

Yes. The 2012 USDA map put 83414 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.