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

Planting zone for 82633 — Douglas, WY

ZIP code 82633 (Douglas, Converse County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 23 and the first fall frost September 22.

Where ZIP 82633 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 23

First frostSep 22

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 Douglas, 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 Douglas, 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 7only 10% chance of frost after

First fall frostSeptember 22median — 10% chance by Sep 9

Growing season122 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around October 1.

From the NOAA station Douglas Converse Co. Airport, WY — 16 miles away, elevation 4,928 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 82633

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 28 – Aug 11

GarlicPlant cloves · Sep 8 – Oct 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 23) and first fall frost (Sep 22) 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 82633 came on Mar 13 — 29 days earlier than the 1991–2020 average (Apr 11).

average
Apr 112026
Mar 13

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 Douglas, WY.

Soil in Douglas, WY

The soil mapped at the center of ZIP 82633 is Hiland — sandy clay loam, well drained.

TextureSandy clay loamholds water and nutrients; slow to drain and warm up

pH7.5slightly alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Hiland-Bowbac complex, 6 to 15 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 82633; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Douglas, WY

Summer high89 °Faverage high, July

Winter low12 °Faverage low, December

Hot days43days a year at 90 °F or more

Freezing nights189nights a year at 32 °F or less

Growing degree days2,282base 50 °F — the season’s usable heat

Longest day15 h 22 mindaylight on June 21

Shortest day9 h 00 mindaylight on December 21

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

Precipitation11.2 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: Douglas Converse Co. Airport, WY (16 mi away); precipitation: Douglas Converse Co. Airport, WY (16 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

822295a

Shawnee, WY · 23 mi

822245a

Lost Springs, WY · 28 mi

826375a

Glenrock, WY · 30 mi

822224b

Lance Creek, WY · 39 mi

822275a

Manville, WY · 40 mi

826365a

Evansville, WY · 41 mi

Wyoming planting zones →

Questions about 82633

What planting zone is ZIP code 82633?

ZIP code 82633 (Douglas, 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 Douglas, WY?

The median last spring frost (32 °F) near 82633 is May 23; after June 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Douglas Converse Co. Airport station.

When is the first frost in Douglas, WY?

The median first fall frost near 82633 is September 22, giving a median frost-free growing season of 122 days.

When should I plant tomatoes in 82633?

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 82633 get?

About 11.2 inches of precipitation a year (NOAA 1991–2020 normals, Douglas Converse Co. Airport station).

How hot do summers get in Douglas, WY?

The average high peaks at 89 °F in July, with about 43 days a year at 90 °F or more.

What kind of soil does 82633 have?

The USDA soil survey maps Hiland at the center of ZIP 82633: sandy clay loam, well drained, pH about 7.5 (slightly alkaline).

Did spring come early in Douglas, WY in 2026?

Spring leaf-out near 82633 came on Mar 13 in 2026, 29 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Douglas, WY?

Long-day onions: the longest day near 82633 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 82633 change?

Yes. The 2012 USDA map put 82633 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.