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

Planting zone for 82723 — Osage, WY

ZIP code 82723 (Osage, Weston County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 20 and the first fall frost September 23.

Where ZIP 82723 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 20

First frostSep 23

2012 zone4b

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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Osage, 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 Osage, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 20median — 50% chance of a later frost

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

First fall frostSeptember 23median — 10% chance by Sep 7

Growing season123 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 9 and returns around October 2.

From the NOAA station Upton, WY — 11 miles away, elevation 4,321 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 82723

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 8 – Apr 22

SpinachSow outdoors · Apr 8 – Apr 29

Broccoli, cabbageStart indoors · Mar 11 – Mar 25

Broccoli, cabbageTransplant · Apr 29 – May 13

Onion setsPlant outdoors · Apr 22 – May 6

PotatoesPlant outdoors · Apr 29 – May 13

LettuceSow outdoors · Apr 22 – May 6

Carrots, beetsSow outdoors · Apr 29 – May 13

TomatoesStart indoors · Mar 25 – Apr 8

TomatoesTransplant · May 27 – Jun 10

Peppers, eggplantStart indoors · Mar 11 – Mar 25

Peppers, eggplantTransplant · Jun 3 – Jun 17

BeansSow outdoors · May 27 – Jun 10

Sweet cornSow outdoors · May 27 – Jun 10

Cucumbers, squashSow outdoors · May 27 – Jun 10

Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12

GarlicPlant cloves · Sep 9 – Oct 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 20) and first fall frost (Sep 23) 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 82723 came on Mar 23 — 19 days earlier than the 1991–2020 average (Apr 11).

average
Apr 112026
Mar 23

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.

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 Osage, WY.

Soil in Osage, WY

The soil mapped at the center of ZIP 82723 is Grummit — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up

pH5.1strongly acidic; 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: Grummit-Maggin association, rolling.

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 82723; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Osage, WY

Summer high87 °Faverage high, July

Winter low10 °Faverage low, January

Hot days31days a year at 90 °F or more

Freezing nights182nights a year at 32 °F or less

Growing degree days2,258base 50 °F — the season’s usable heat

Longest day15 h 29 mindaylight on June 21

Shortest day8 h 53 mindaylight on December 21

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

Precipitation16.2 inper year, rain and melted snow

Snowfall46 inper year; 77 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: Upton, WY (11 mi away); precipitation: Upton, WY (11 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.

827304b

Upton, WY · 15 mi

827014b

Newcastle, WY · 21 mi

827294b

Sundance, WY · 26 mi

577454b

Hill City, SD · 32 mi

577545a

Lead, SD · 33 mi

827214b

Moorcroft, WY · 40 mi

827125a

Beulah, WY · 40 mi

827144b

Devils Tower, WY · 41 mi

Wyoming planting zones →

Questions about 82723

What planting zone is ZIP code 82723?

ZIP code 82723 (Osage, 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 Osage, WY?

The median last spring frost (32 °F) near 82723 is May 20; after June 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Upton station.

When is the first frost in Osage, WY?

The median first fall frost near 82723 is September 23, giving a median frost-free growing season of 123 days.

When should I plant tomatoes in 82723?

Start tomato seeds indoors around Mar 25 – Apr 8 and set transplants outside around May 27 – Jun 10, one to three weeks after the median last frost.

How much rain and snow does 82723 get?

About 16.2 inches of precipitation a year and 46 inches of snowfall (NOAA 1991–2020 normals, Upton station).

How hot do summers get in Osage, WY?

The average high peaks at 87 °F in July, with about 31 days a year at 90 °F or more.

What kind of soil does 82723 have?

The USDA soil survey maps Grummit at the center of ZIP 82723: clay loam, well drained, pH about 5.1 (strongly acidic).

Did spring come early in Osage, WY in 2026?

Spring leaf-out near 82723 came on Mar 23 in 2026, 19 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Osage, WY?

Long-day onions: the longest day near 82723 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).