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

Planting zone for 82215 — Hartville, WY

ZIP code 82215 (Hartville, Platte County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 25 and the first fall frost September 15.

Where ZIP 82215 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 25

First frostSep 15

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 Hartville, 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 Hartville, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 25median — 50% chance of a later frost

Safe for tender plantsJune 11only 10% chance of frost after

First fall frostSeptember 15median — 10% chance by Sep 4

Growing season112 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 13 and returns around September 24.

From the NOAA station Glendo 6ne, WY — 12 miles away, elevation 4,738 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 82215

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 13 – Apr 27

SpinachSow outdoors · Apr 13 – May 4

Broccoli, cabbageStart indoors · Mar 16 – Mar 30

Broccoli, cabbageTransplant · May 4 – May 18

Onion setsPlant outdoors · Apr 27 – May 11

PotatoesPlant outdoors · May 4 – May 18

LettuceSow outdoors · Apr 27 – May 11

Carrots, beetsSow outdoors · May 4 – May 18

TomatoesStart indoors · Mar 30 – Apr 13

TomatoesTransplant · Jun 1 – Jun 15

Peppers, eggplantStart indoors · Mar 16 – Mar 30

Peppers, eggplantTransplant · Jun 8 – Jun 22

BeansSow outdoors · Jun 1 – Jun 15

Sweet cornSow outdoors · Jun 1 – Jun 15

Cucumbers, squashSow outdoors · Jun 1 – Jun 15

Fall lettuce, spinachSow outdoors · Jul 21 – Aug 4

GarlicPlant cloves · Sep 1 – Oct 6

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 25) and first fall frost (Sep 15) 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 82215 came on Mar 10 — 31 days earlier than the 1991–2020 average (Apr 10).

average
Apr 102026
Mar 10

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 Hartville, WY.

Soil in Hartville, WY

The soil mapped at the center of ZIP 82215 is Wendover — very cobbly fine sandy loam, well drained.

TextureVery cobbly fine sandy loamdrains and warms fast; dries out and needs more feeding

pH7.6slightly alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Wendover-Rock outcrop complex, 10 to 60 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 82215; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hartville, WY

Summer high87 °Faverage high, July

Winter low6 °Faverage low, December

Hot days38days a year at 90 °F or more

Freezing nights204nights a year at 32 °F or less

Growing degree days2,103base 50 °F — the season’s usable heat

Longest day15 h 18 mindaylight on June 21

Shortest day9 h 04 mindaylight on December 21

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

Precipitation13.4 inper year, rain and melted snow

Snowfall44 inper year; 63 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: Glendo 6ne, WY (12 mi away); precipitation: Glendo 6ne, WY (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

Fort Laramie, WY · 17 mi

822275a

Manville, WY · 17 mi

822245a

Lost Springs, WY · 27 mi

822235a

Lingle, WY · 29 mi

822425a

Van Tassell, WY · 31 mi

Wyoming planting zones →

Questions about 82215

What planting zone is ZIP code 82215?

ZIP code 82215 (Hartville, 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 Hartville, WY?

The median last spring frost (32 °F) near 82215 is May 25; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Glendo 6ne station.

When is the first frost in Hartville, WY?

The median first fall frost near 82215 is September 15, giving a median frost-free growing season of 112 days.

When should I plant tomatoes in 82215?

Start tomato seeds indoors around Mar 30 – Apr 13 and set transplants outside around Jun 1 – Jun 15, one to three weeks after the median last frost.

How much rain and snow does 82215 get?

About 13.4 inches of precipitation a year and 44 inches of snowfall (NOAA 1991–2020 normals, Glendo 6ne station).

How hot do summers get in Hartville, WY?

The average high peaks at 87 °F in July, with about 38 days a year at 90 °F or more.

What kind of soil does 82215 have?

The USDA soil survey maps Wendover at the center of ZIP 82215: very cobbly fine sandy loam, well drained, pH about 7.6 (slightly alkaline).

Did spring come early in Hartville, WY in 2026?

Spring leaf-out near 82215 came on Mar 10 in 2026, 31 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hartville, WY?

Long-day onions: the longest day near 82215 is 15 h 18 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 82215 change?

Yes. The 2012 USDA map put 82215 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.