Weston County, in Wyoming, sits in USDA hardiness zone 4b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Well-matched crops include cabbage, cranberry, turkish rocket, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Weston County holds more than one microclimate.
Soils and elevations shift across Weston County, so your frost dates and drainage aren't the county average. 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 Weston County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Weston County — the short answer
Weston County, Wyoming: USDA zone 4b, about 155 days between hard freezes, across 1.5M acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 8
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~155
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.5M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 4b is Weston County's average, not your lot's — a low corner or a tree line moves it. Against Weston County's 155-day season, see what your own ground reads.
Heat in Weston County
Across a year, Weston County accumulates about 2,222 growing degree days above 50°F, about 348 more than the middle Wyoming county — ahead of 19 of Wyoming’s 23 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Weston County
Across Weston County, the ground is predominantly Entisols, where Theedle, Shingle, and Tassel are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 7.2–7.9, slightly alkaline. Rainfall drains through hydrologic group D soils.
Soil order
Entisols
Drainage
Well drained
Prime farmland
1%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Weston County
The USDA soil survey maps 98% of Weston County as well drained — but another 1% drains differently: 1% excessively drained.
Theedle is the most extensive named soil at 9% of mapped acres, then Shingle (8%) and Tassel (6%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Weston County
Each reading below is measured for Weston County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Weston County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Weston County runs about pH 7.2–7.9, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Season length
MeasuredWeston County runs about 155 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredWeston County sits in USDA hardiness zone 4b.
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 Weston County is in
Weston County spans 2 EPA Level III ecoregions — Northwestern Great Plains (82%) and Middle Rockies (18%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Weston County
We scored all 1,086 plants against Weston County's own USDA zone 4b and its own 155-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Wyoming profile.
Is it too late to plant in Weston County?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 8 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What gets applied to farmland in Weston County
USGS estimates 7,083 lb of Glyphosate on Weston County farmland in 2019, its largest by weight, ahead of 2,4-d (4,648 lb) and Dicamba (2,255 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Weston County — and how to grow with it.
We checked the federal record across Weston County — 152 documented sites across 7 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Weston County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Weston County
Closest first, across Weston County. Listing isn't leaking, and distance isn't exposure.
- 46-065-23bad01Nitrate · 8.1 mi
- 46-064-13cc 02Nitrate · 8.7 mi
- 43N 065W 11AC 01Nitrate · 9.0 mi
- 46-063-17cbc02Nitrate · 9.7 mi
- BUTTE/MUSH CREEK JUNCTIONBrownfields · 10.0 mi
- THUNDER CREEK STATIONBrownfields · 10.0 mi
- WYOMING PIPELINE-MUSH CREEK JUNCTIONBrownfields · 10.0 mi
- CLARETON PUMP STATIONBrownfields · 10.4 mi
- 44-063-26cac01Nitrate · 10.5 mi
- Petro Lewis - Osage OfficeUnderground Storage Tanks · 11.0 mi
- BLACK HILLS POWER AND LIGHT COMPANY - OSAGE POWER PLANTToxics Release Inventory · 11.6 mi
- Baroid Drilling Fluids, Inc.Underground Storage Tanks · 11.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Weston County'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 Weston County.
Total Sites
152
across Weston County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Weston County
Severity Distribution
across Weston County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Weston County, Nitrate runs higher than the national average — 68 sites across Weston County. That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Weston County
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 Weston County average
Your land is one point inside Weston County
Everything above resolves to Weston County as a whole — one PHZM band and one county frost record, read across 1.5M 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 county 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 county average.
Your Lot vs the Weston County Average
Weston County Average
- ●USDA Zones 4b, averaged across Weston County
- ●One soil character for all of Weston County
- ●Frost dates read at Weston County's scale: May 6 to Oct 8
YOUR Parcel
- ✓Your exact zone, not Weston County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Weston County
Pull a site-specific report for your exact address in Weston County, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Weston County averages can't show:
We read public map data around Weston County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Weston County average
How we know this about Weston County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Weston County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Weston County
When does frost risk typically end in Weston County?
The last hard freeze (28°F) in Weston County typically lands around May 6, 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 27.
How long is the growing season in Weston County?
Measured between 28°F hard freezes, Weston County sees about 155 frost-free days — roughly May 6 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 24, about 120 days.
Is the soil safe to grow vegetables in Weston County?
The federal record around Weston County is a meaningful one — 152 documented sites, mostly Nitrate entries (68), the nearest Nitrate record about 8.1 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
Everything above is measured at Weston County's scale — its 4b band and its 155-day season. Your yard writes its own version of Weston County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Wyoming's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Weston County’s own scale
8 of the readings below were taken at Weston County's own scale — its own ~155-day span between 28°F freezes, the 3 most extensive soil series mapped here and 152 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Weston County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Weston County's own 28°F hard-freeze dates and its ~155-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Weston CountyUSDA NRCS SSURGO
- 152 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 8.1 miles outFederal environmental registers
- Weston County's boundary and the 1,534,722 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~155-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Weston County spans, Northwestern Great Plains the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Weston County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Wyoming grower plans around — written at state scale, so they stay on the state guidefrom Wyoming
What this page can’t tell you
- How the season shifts across Weston County — the ~155 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Weston County's 1,534,722 acreswhy one lot differs from the next →
- Which of those 152 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Weston Countyread your own land →