Powder River, Wyoming, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Powder River, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Powder River lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Powder River — soil, climate, flood, and parcel records. How we handle your address.
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Powder River — the short answer
Powder River, Wyoming: USDA zone 5a, about 143 days between hard freezes, across 4K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~143
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5a is Powder River's average, not your lot's — a low corner or a tree line moves it. Against Powder River's 143-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Powder River
Each reading below is measured for Powder River itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPowder River runs about 143 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredPowder River sits in USDA hardiness zone 5a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Powder River is in
Powder River sits in the Wyoming Basin — EPA Level III, inside the wider North American Deserts. That is read at Powder River's own centroid rather than borrowed from Natrona County.
What Grows in Powder River
Every plant below cleared Powder River's own zone 5a and its 143-day season. Each card opens that plant's Wyoming profile. How we score.
Is it too late to plant in Powder River?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 29 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What's on the federal record near Powder River
Closest first, within ~10 miles of Powder River. Listing isn't leaking, and distance isn't exposure.
- Supply WagonUnderground Storage Tanks · 1.4 mi
- HHA, Inc.Underground Storage Tanks · 1.4 mi
- Waltman StoreUnderground Storage Tanks · 1.4 mi
Measured from Powder River's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Powder River.
Total Sites
3
within ~10 miles of Powder River
Risk Level
Low
Highest-severity
3 underground storage tanks
Severity Distribution
within ~10 miles of Powder River
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
Check your specific parcel in Powder River
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Powder River average
Your land is one point inside Powder River
Everything above resolves to Powder River as a whole — one PHZM band and one 28°F frost record, read across 4K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Powder River Average
Powder River Average
- ●USDA Zones 5a, averaged across Powder River
- ●One soil character for all of Powder River
- ●Frost dates read at Powder River's scale: May 9 to Sep 29
YOUR Parcel
- ✓Your exact zone, not Powder River's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Powder River
Pull a site-specific report for your exact address in Powder River, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Powder River averages can't show:
We read public map data around Powder River — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Powder River average
How we know this about Powder River
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Powder River’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Powder River
When does frost risk typically end in Powder River?
The last hard freeze (28°F) in Powder River typically lands around May 9, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 30.
When is the first frost in Powder River?
The first hard freeze (28°F) in Powder River typically arrives around Sep 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 15, so the watching starts about Aug 30 — about 143 days after the spring freeze cleared.
How long is the growing season in Powder River?
Measured between 28°F hard freezes, Powder River sees about 143 frost-free days — roughly May 9 through Sep 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 30 to Sep 15, about 108 days.
Is the soil safe to grow vegetables in Powder River?
The federal record around Powder River is light — 3 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (3), the nearest Underground Storage Tanks record about 1.4 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do gardeners stretch the season in Powder River?
With about 143 frost-free days between hard freezes, Powder River rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 171 to 199 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 9 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Powder River's scale — its 5a band and its 143-day season. Your yard writes its own version of Powder River's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Powder River’s own scale
6 of the readings below were taken at Powder River's own scale — its own ~143-day season between 28°F freezes, the 3,791 acres it covers and 3 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Powder River's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Powder River's own 28°F hard-freeze dates, about May 9 and Sep 29 and the ~143-day span between themNOAA 1991–2020 Climate Normals
- 3 documented contamination sites on the federal record near Powder River, the closest Underground Storage Tanks record about 1.4 miles out from the town centreFederal environmental registers
- Powder River's boundary and the 3,791 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~143-day seasonGrowable Ground crop-matching engine
- The ecoregion at Powder River's own centroid, the Wyoming BasinUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Powder River's 3,791 acres read through its county's SSURGO summaryfrom Natrona County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Natrona County
- The growing challenges every Wyoming grower plans around — written at state scale, so they stay on the state guidefrom Wyoming
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Natrona County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Powder River's 3,791 acreswhy one lot differs from the next →
- Which side of Powder River you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,791 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.4 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Powder River-wide figureread your own land →
More in Wyoming
Wider growing context
What grows across WyomingPowder River sits outside our named growing regions, so Wyoming as a whole is its closest context here.
Nearby growing guides