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

Planting zone for 82731 — Weston, WY

ZIP code 82731 (Weston, Campbell County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 23 and the first fall frost September 18.

Where ZIP 82731 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.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostMay 23
First frostSep 18
2012 zone4a

Was 4a 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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Weston, 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 Weston, WY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 23median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostSeptember 18median — 10% chance by Sep 1
Growing season118 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 11 and returns around September 29.

From the NOAA station Weston 1 E, WY — 12 miles away, elevation 3,737 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 82731

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 11 – Apr 25
SpinachSow outdoors · Apr 11 – May 2
Broccoli, cabbageStart indoors · Mar 14 – Mar 28
Broccoli, cabbageTransplant · May 2 – May 16
Onion setsPlant outdoors · Apr 25 – May 9
PotatoesPlant outdoors · May 2 – May 16
LettuceSow outdoors · Apr 25 – May 9
Carrots, beetsSow outdoors · May 2 – May 16
TomatoesStart indoors · Mar 28 – Apr 11
TomatoesTransplant · May 30 – Jun 13
Peppers, eggplantStart indoors · Mar 14 – Mar 28
Peppers, eggplantTransplant · Jun 6 – Jun 20
BeansSow outdoors · May 30 – Jun 13
Sweet cornSow outdoors · May 30 – Jun 13
Cucumbers, squashSow outdoors · May 30 – Jun 13
Fall lettuce, spinachSow outdoors · Jul 24 – Aug 7
GarlicPlant cloves · Sep 4 – Oct 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 23) and first fall frost (Sep 18) 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 82731 came on Mar 22 — 20 days earlier than the 1991–2020 average (Apr 11).

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 4b in Wyoming

495 plants native to the lower 48 states, recorded in Wyoming, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

Trees 22

American elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °FDouglas-fir200 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 83

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °F

Wildflowers & perennials 226

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °F

Grasses 152

Alaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 3

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

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 Weston, WY.

Soil in Weston, WY

The soil mapped at the center of ZIP 82731 is Ucross — loam, well drained.

TextureLoama good balance for most vegetables
pH8.1alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Ucross-Iwait-Fairburn 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 82731; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Weston, WY

Summer high87 °Faverage high, July
Winter low10 °Faverage low, January
Hot days36days a year at 90 °F or more
Freezing nights188nights a year at 32 °F or less
Growing degree days2,198base 50 °F — the season’s usable heat
Longest day15 h 35 mindaylight on June 21
Shortest day8 h 47 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation16.8 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 37 °F, low 10 °F 37°10° JanFebruary: average high 39 °F, low 13 °F 39°13° FebMarch: average high 51 °F, low 22 °F 51°22° MarApril: average high 57 °F, low 30 °F 57°30° AprMay: average high 66 °F, low 39 °F 66°39° MayJune: average high 78 °F, low 48 °F 78°48° JunJuly: average high 87 °F, low 54 °F 87°54° JulAugust: average high 87 °F, low 52 °F 87°52° AugSeptember: average high 76 °F, low 42 °F 76°42° SepOctober: average high 60 °F, low 31 °F 60°31° OctNovember: average high 47 °F, low 19 °F 47°19° NovDecember: average high 37 °F, low 11 °F 37°11° Dec

Precipitation by month inches

0″1″2″3″January: 0.53 in precipitation 0.5 JanFebruary: 0.61 in precipitation 0.6 FebMarch: 0.98 in precipitation 1.0 MarApril: 1.89 in precipitation 1.9 AprMay: 2.88 in precipitation 2.9 MayJune: 2.40 in precipitation 2.4 JunJuly: 1.92 in precipitation 1.9 JulAugust: 1.52 in precipitation 1.5 AugSeptember: 1.16 in precipitation 1.2 SepOctober: 1.77 in precipitation 1.8 OctNovember: 0.48 in precipitation 0.5 NovDecember: 0.65 in precipitation 0.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Weston 1 E, WY (12 mi away); precipitation: Weston 10.9 Ne, WY (2 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.

593144b
Biddle, MT · 21 mi
827255a
Recluse, WY · 24 mi
827204b
Hulett, WY · 27 mi
827165a
Gillette, WY · 28 mi
827214b
Moorcroft, WY · 29 mi
827144b
Devils Tower, WY · 32 mi
827274b
Rozet, WY · 32 mi
827175a
Gillette, WY · 37 mi

Wyoming planting zones →

Questions about 82731

What planting zone is ZIP code 82731?

ZIP code 82731 (Weston, WY) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Weston, WY?

The median last spring frost (32 °F) near 82731 is May 23; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Weston 1 E station.

When is the first frost in Weston, WY?

The median first fall frost near 82731 is September 18, giving a median frost-free growing season of 118 days.

When should I plant tomatoes in 82731?

Start tomato seeds indoors around Mar 28 – Apr 11 and set transplants outside around May 30 – Jun 13, one to three weeks after the median last frost.

How much rain and snow does 82731 get?

About 16.8 inches of precipitation a year (NOAA 1991–2020 normals, Weston 10.9 Ne station).

How hot do summers get in Weston, WY?

The average high peaks at 87 °F in July, with about 36 days a year at 90 °F or more.

What kind of soil does 82731 have?

The USDA soil survey maps Ucross at the center of ZIP 82731: loam, well drained, pH about 8.1 (alkaline).

Did spring come early in Weston, WY in 2026?

Spring leaf-out near 82731 came on Mar 22 in 2026, 20 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Weston, WY?

Long-day onions: the longest day near 82731 is 15 h 35 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 82731 change?

Yes. The 2012 USDA map put 82731 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.