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

Planting zone for 82945 — Superior, WY

ZIP code 82945 (Superior, Sweetwater County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 22 and the first fall frost September 28.

Where ZIP 82945 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 22

First frostSep 28

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 Superior, 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 Superior, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 22median — 50% chance of a later frost

Safe for tender plantsJune 9only 10% chance of frost after

First fall frostSeptember 28median — 10% chance by Sep 14

Growing season126 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 7 and returns around October 5.

From the NOAA station Rock Springs Airport, WY — 11 miles away, elevation 6,742 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 82945

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 10 – Apr 24

SpinachSow outdoors · Apr 10 – May 1

Broccoli, cabbageStart indoors · Mar 13 – Mar 27

Broccoli, cabbageTransplant · May 1 – May 15

Onion setsPlant outdoors · Apr 24 – May 8

PotatoesPlant outdoors · May 1 – May 15

LettuceSow outdoors · Apr 24 – May 8

Carrots, beetsSow outdoors · May 1 – May 15

TomatoesStart indoors · Mar 27 – Apr 10

TomatoesTransplant · May 29 – Jun 12

Peppers, eggplantStart indoors · Mar 13 – Mar 27

Peppers, eggplantTransplant · Jun 5 – Jun 19

BeansSow outdoors · May 29 – Jun 12

Sweet cornSow outdoors · May 29 – Jun 12

Cucumbers, squashSow outdoors · May 29 – Jun 12

Fall lettuce, spinachSow outdoors · Aug 3 – Aug 17

GarlicPlant cloves · Sep 14 – Oct 19

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 22) and first fall frost (Sep 28) 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 82945 came on Apr 3 — 22 days earlier than the 1991–2020 average (Apr 25).

average
Apr 252026
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 Superior, WY.

Soil in Superior, WY

The soil mapped at the center of ZIP 82945 is Frandsen — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.25%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Frandsen-Alona family-Lonna family, complex, 1 to 4 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 82945; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Superior, WY

Summer high84 °Faverage high, July

Winter low13 °Faverage low, December

Hot days10days a year at 90 °F or more

Freezing nights189nights a year at 32 °F or less

Growing degree days1,914base 50 °F — the season’s usable heat

Longest day15 h 13 mindaylight on June 21

Shortest day9 h 09 mindaylight on December 21

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

Precipitation7.5 inper year, rain and melted snow

Snowfall54 inper year; 69 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: Rock Springs Airport, WY (11 mi away); precipitation: Rock Springs Airport, WY (11 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.

829425a

Point Of Rocks, WY · 9 mi

829435a

Reliance, WY · 13 mi

829025a

Rock Springs, WY · 16 mi

829015b

Rock Springs, WY · 24 mi

829324a

Farson, WY · 36 mi

829355a

Green River, WY · 37 mi

823364b

Wamsutter, WY · 38 mi

829295a

Little America, WY · 50 mi

Wyoming planting zones →

Questions about 82945

What planting zone is ZIP code 82945?

ZIP code 82945 (Superior, 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 Superior, WY?

The median last spring frost (32 °F) near 82945 is May 22; after June 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rock Springs Airport station.

When is the first frost in Superior, WY?

The median first fall frost near 82945 is September 28, giving a median frost-free growing season of 126 days.

When should I plant tomatoes in 82945?

Start tomato seeds indoors around Mar 27 – Apr 10 and set transplants outside around May 29 – Jun 12, one to three weeks after the median last frost.

How much rain and snow does 82945 get?

About 7.5 inches of precipitation a year and 54 inches of snowfall (NOAA 1991–2020 normals, Rock Springs Airport station).

How hot do summers get in Superior, WY?

The average high peaks at 84 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 82945 have?

The USDA soil survey maps Frandsen at the center of ZIP 82945: silt loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Superior, WY in 2026?

Spring leaf-out near 82945 came on Apr 3 in 2026, 22 days earlier than the 1991–2020 average (Apr 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Superior, WY?

Long-day onions: the longest day near 82945 is 15 h 13 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).