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

Planting zone for 83122 — Grover, WY

ZIP code 83122 (Grover, Lincoln County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is June 20 and the first fall frost September 1.

Where ZIP 83122 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 frostJun 20

First frostSep 1

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 Grover, 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 Grover, WY

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsJuly 7only 10% chance of frost after

First fall frostSeptember 1median — 10% chance by Aug 12

Growing season71 daysfrost-free, median

A hard freeze (28 °F) usually ends around June 1 and returns around September 13.

From the NOAA station Afton, WY — 6 miles away, elevation 6,247 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 83122

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · May 9 – May 23

SpinachSow outdoors · May 9 – May 30

Broccoli, cabbageStart indoors · Apr 11 – Apr 25

Broccoli, cabbageTransplant · May 30 – Jun 13

Onion setsPlant outdoors · May 23 – Jun 6

PotatoesPlant outdoors · May 30 – Jun 13

LettuceSow outdoors · May 23 – Jun 6

Carrots, beetsSow outdoors · May 30 – Jun 13

TomatoesStart indoors · Apr 25 – May 9

TomatoesTransplant · Jun 27 – Jul 11

Peppers, eggplantStart indoors · Apr 11 – Apr 25

Peppers, eggplantTransplant · Jul 4 – Jul 18

BeansSow outdoors · Jun 27 – Jul 11

Sweet cornSow outdoors · Jun 27 – Jul 11

Cucumbers, squashSow outdoors · Jun 27 – Jul 11

Fall lettuce, spinachSow outdoors · Jul 7 – Jul 21

GarlicPlant cloves · Aug 18 – Sep 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 20) and first fall frost (Sep 1) 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 83122 came on Apr 7 — 25 days earlier than the 1991–2020 average (May 2).

average
May 22026
Apr 7

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 Grover, WY.

Soil in Grover, WY

The soil mapped at the center of ZIP 83122 is Robana — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.6neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Robana silt loam, 10 to 20 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 83122; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Grover, WY

Summer high80 °Faverage high, July

Winter low6 °Faverage low, January

Hot days2days a year at 90 °F or more

Freezing nights238nights a year at 32 °F or less

Growing degree days1,027base 50 °F — the season’s usable heat

Longest day15 h 20 mindaylight on June 21

Shortest day9 h 01 mindaylight on December 21

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

Precipitation25.3 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: Bedford 3 Se, WY (4 mi away); precipitation: Bedford 3 Se, WY (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Wyoming planting zones →

Questions about 83122

What planting zone is ZIP code 83122?

ZIP code 83122 (Grover, 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 Grover, WY?

The median last spring frost (32 °F) near 83122 is June 20; after July 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Afton station.

When is the first frost in Grover, WY?

The median first fall frost near 83122 is September 1, giving a median frost-free growing season of 71 days.

When should I plant tomatoes in 83122?

Start tomato seeds indoors around Apr 25 – May 9 and set transplants outside around Jun 27 – Jul 11, one to three weeks after the median last frost.

How much rain and snow does 83122 get?

About 25.3 inches of precipitation a year (NOAA 1991–2020 normals, Bedford 3 Se station).

How hot do summers get in Grover, WY?

The average high peaks at 80 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 83122 have?

The USDA soil survey maps Robana at the center of ZIP 83122: silt loam, well drained, pH about 6.6 (neutral).

Did spring come early in Grover, WY in 2026?

Spring leaf-out near 83122 came on Apr 7 in 2026, 25 days earlier than the 1991–2020 average (May 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Grover, WY?

Long-day onions: the longest day near 83122 is 15 h 20 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).