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

Planting zone for 82931 — Evanston, WY

ZIP code 82931 (Evanston, Uinta County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 12 and the first fall frost September 12.

Where ZIP 82931 is

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 12

First frostSep 12

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 Evanston, 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 Evanston, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 12median — 50% chance of a later frost

Safe for tender plantsJuly 2only 10% chance of frost after

First fall frostSeptember 12median — 10% chance by Aug 26

Growing season90 daysfrost-free, median

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

From the NOAA station Evanston 1 E, WY — 2 miles away, elevation 6,824 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 82931

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · May 1 – May 15

SpinachSow outdoors · May 1 – May 22

Broccoli, cabbageStart indoors · Apr 3 – Apr 17

Broccoli, cabbageTransplant · May 22 – Jun 5

Onion setsPlant outdoors · May 15 – May 29

PotatoesPlant outdoors · May 22 – Jun 5

LettuceSow outdoors · May 15 – May 29

Carrots, beetsSow outdoors · May 22 – Jun 5

TomatoesStart indoors · Apr 17 – May 1

TomatoesTransplant · Jun 19 – Jul 3

Peppers, eggplantStart indoors · Apr 3 – Apr 17

Peppers, eggplantTransplant · Jun 26 – Jul 10

BeansSow outdoors · Jun 19 – Jul 3

Sweet cornSow outdoors · Jun 19 – Jul 3

Cucumbers, squashSow outdoors · Jun 19 – Jul 3

Fall lettuce, spinachSow outdoors · Jul 18 – Aug 1

GarlicPlant cloves · Aug 29 – Oct 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 12) and first fall frost (Sep 12) 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 82931 came on Apr 3 — 25 days earlier than the 1991–2020 average (Apr 28).

average
Apr 282026
Apr 3

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 Evanston, WY.

Soil in Evanston, WY

The soil mapped at the center of ZIP 82931 is Almaholt - draft — loam, well drained.

TextureLoama good balance for most vegetables

pH8.0alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Almaholt-Roundor-High loams, 3 to 30 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 82931; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Evanston, WY

Summer high81 °Faverage high, July

Winter low11 °Faverage low, January

Hot days2days a year at 90 °F or more

Freezing nights210nights a year at 32 °F or less

Growing degree days1,359base 50 °F — the season’s usable heat

Longest day15 h 09 mindaylight on June 21

Shortest day9 h 12 mindaylight on December 21

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

Precipitation12.1 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: Evanston 1 E, WY (2 mi away); precipitation: Evanston 1 E, WY (2 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.

840865a

Woodruff, UT · 18 mi

829335b

Fort Bridger, WY · 22 mi

829445a

Robertson, WY · 24 mi

840175b

Coalville, UT · 26 mi

Mountain View, WY · 30 mi

840644a

Randolph, UT · 31 mi

All 2 ZIP codes in Evanston → · Wyoming planting zones →

Questions about 82931

What planting zone is ZIP code 82931?

ZIP code 82931 (Evanston, 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 Evanston, WY?

The median last spring frost (32 °F) near 82931 is June 12; after July 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Evanston 1 E station.

When is the first frost in Evanston, WY?

The median first fall frost near 82931 is September 12, giving a median frost-free growing season of 90 days.

When should I plant tomatoes in 82931?

Start tomato seeds indoors around Apr 17 – May 1 and set transplants outside around Jun 19 – Jul 3, one to three weeks after the median last frost.

How much rain and snow does 82931 get?

About 12.1 inches of precipitation a year (NOAA 1991–2020 normals, Evanston 1 E station).

How hot do summers get in Evanston, WY?

The average high peaks at 81 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 82931 have?

The USDA soil survey maps Almaholt - draft at the center of ZIP 82931: loam, well drained, pH about 8.0 (alkaline).

Did spring come early in Evanston, WY in 2026?

Spring leaf-out near 82931 came on Apr 3 in 2026, 25 days earlier than the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Evanston, WY?

Long-day onions: the longest day near 82931 is 15 h 09 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).