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

Planting zone for 82334 — Sinclair, WY

ZIP code 82334 (Sinclair, Carbon County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 12 and the first fall frost October 4.

Where ZIP 82334 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 12

First frostOct 4

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 Sinclair, 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 Sinclair, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsMay 25only 10% chance of frost after

First fall frostOctober 4median — 10% chance by Sep 23

Growing season143 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 12.

From the NOAA station Seminoe Rsvr Usbr, WY — 14 miles away, elevation 6,975 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 82334

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 31 – Apr 14

SpinachSow outdoors · Mar 31 – Apr 21

Broccoli, cabbageStart indoors · Mar 3 – Mar 17

Broccoli, cabbageTransplant · Apr 21 – May 5

Onion setsPlant outdoors · Apr 14 – Apr 28

PotatoesPlant outdoors · Apr 21 – May 5

LettuceSow outdoors · Apr 14 – Apr 28

Carrots, beetsSow outdoors · Apr 21 – May 5

TomatoesStart indoors · Mar 17 – Mar 31

TomatoesTransplant · May 19 – Jun 2

Peppers, eggplantStart indoors · Mar 3 – Mar 17

Peppers, eggplantTransplant · May 26 – Jun 9

BeansSow outdoors · May 19 – Jun 2

Sweet cornSow outdoors · May 19 – Jun 2

Cucumbers, squashSow outdoors · May 19 – Jun 2

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 12) 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 82334 came on Mar 25 — 28 days earlier than the 1991–2020 average (Apr 22).

average
Apr 222026
Mar 25

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 Sinclair, WY.

Soil in Sinclair, WY

The soil mapped at the center of ZIP 82334 is Poposhia — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

DrainageWell drainednatural drainage class

Organic matter1%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Poposhia-Havre overflow complex, 0 to 6 percent slopes -- draft.

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 82334; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sinclair, WY

Summer high84 °Faverage high, July

Winter low14 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights173nights a year at 32 °F or less

Growing degree days1,983base 50 °F — the season’s usable heat

Longest day15 h 14 mindaylight on June 21

Shortest day9 h 07 mindaylight on December 21

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

Precipitation13.2 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: Seminoe Rsvr Usbr, WY (14 mi away); precipitation: Seminoe Rsvr Usbr, WY (14 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.

823355a

Walcott, WY · 15 mi

826154b

Shirley Basin, WY · 16 mi

Elk Mountain, WY · 35 mi

Wyoming planting zones →

Questions about 82334

What planting zone is ZIP code 82334?

ZIP code 82334 (Sinclair, 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 Sinclair, WY?

The median last spring frost (32 °F) near 82334 is May 12; after May 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Seminoe Rsvr Usbr station.

When is the first frost in Sinclair, WY?

The median first fall frost near 82334 is October 4, giving a median frost-free growing season of 143 days.

When should I plant tomatoes in 82334?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 82334 get?

About 13.2 inches of precipitation a year (NOAA 1991–2020 normals, Seminoe Rsvr Usbr station).

How hot do summers get in Sinclair, WY?

The average high peaks at 84 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 82334 have?

The USDA soil survey maps Poposhia at the center of ZIP 82334: sandy loam, well drained.

Did spring come early in Sinclair, WY in 2026?

Spring leaf-out near 82334 came on Mar 25 in 2026, 28 days earlier than the 1991–2020 average (Apr 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sinclair, WY?

Long-day onions: the longest day near 82334 is 15 h 14 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 82334 change?

Yes. The 2012 USDA map put 82334 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.