Sublette County, in Wyoming, sits in USDA hardiness zone 4b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Well-matched crops include zucchini, cranberry, cilantro, and pumpkin, 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
Sublette County holds more than one microclimate.
Soils and elevations shift across Sublette 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 Sublette County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Sublette County — the short answer
Sublette County, Wyoming: USDA zone 4b, about 89 days between hard freezes, across 3.1M acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jun 9
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 6
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~89
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 3.1M 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 Sublette County's average, not your lot's — a low corner or a tree line moves it. Against Sublette County's 89-day season, see what your own ground reads.
Heat in Sublette County
Across a year, Sublette County accumulates about 632 growing degree days above 50°F, about 1,242 fewer than the middle Wyoming county — ahead of 2 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 Sublette County
Across Sublette County, the ground is predominantly Mollisols, where Jemdilon, Jonah, and Foreright are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 6.4–7.6, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
3%
Soil still varies lot by lot — soil types explained.
How the ground varies across Sublette County
The USDA soil survey maps 79% of Sublette County as well drained — but another 12% drains differently: 7% somewhat poorly drained, 2% very poorly drained.
Jemdilon is the most extensive named soil at 3% of mapped acres, then Jonah (2%) and Foreright (2%).
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 Sublette County
Each reading below is measured for Sublette 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 Sublette County are well drained, in hydrologic group C — 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 Sublette County runs about pH 6.4–7.6, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredSublette County runs about 89 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
MeasuredSublette 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 Sublette County is in
Sublette County spans 2 EPA Level III ecoregions — Wyoming Basin (59%) and Middle Rockies (41%). 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 Sublette County
We scored all 1,086 plants against Sublette County's own USDA zone 4b and its own 89-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 Sublette County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around May 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jun 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 6 — long-season crops need about 90 days of runway, quick greens only 30. Even here the calendar’s edges hold value: thirty-day greens late in the window, then garlic and a rested bed for spring.
What gets applied to farmland in Sublette County
USGS estimates 2,049 lb of 2,4-d on Sublette County farmland in 2019, its largest by weight, ahead of Chlorpyrifos (2,006 lb) and Glyphosate (1,409 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 Sublette County — and how to grow with it.
We checked the federal record across Sublette County — 260 documented sites across 5 of the 9 source types we track.
The most significant on record: 3 Superfund sites (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 Sublette 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 Sublette County
Closest first, across Sublette County. Listing isn't leaking, and distance isn't exposure.
- Ralph Wenz FieldUnderground Storage Tanks · 5.9 mi
- Dew Lumber Company, Inc.Underground Storage Tanks · 6.1 mi
- Bob's Oil TanksUnderground Storage Tanks · 6.2 mi
- 33-109-09aad01Nitrate · 6.2 mi
- 33-109-09aba01Nitrate · 6.2 mi
- TROY'S MOTORSPORTS AND TOWING COMPANYBrownfields · 6.2 mi
- WY Department of TransportationUnderground Storage Tanks · 7.0 mi
- UPS - PINEDALEBrownfields · 7.0 mi
- Country Lane Groceries and GasUnderground Storage Tanks · 7.0 mi
- Bucky's RepairUnderground Storage Tanks · 7.1 mi
- T-7, Inc. Propane Sales and ServiceUnderground Storage Tanks · 7.1 mi
- 33-109-04baa01Nitrate · 7.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Sublette 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 Sublette County.
Total Sites
260
across Sublette County
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
across Sublette County
Severity Distribution
across Sublette County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Sublette County, Nitrate runs higher than the national average — 164 sites across Sublette County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 Sublette 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 Sublette County average
Your land is one point inside Sublette County
Everything above resolves to Sublette County as a whole — one PHZM band and one county frost record, read across 3.1M 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 Sublette County Average
Sublette County Average
- ●USDA Zones 4b, averaged across Sublette County
- ●One soil character for all of Sublette County
- ●Frost dates read at Sublette County's scale: Jun 9 to Sep 6
YOUR Parcel
- ✓Your exact zone, not Sublette County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Sublette County
Pull a site-specific report for your exact address in Sublette County, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Sublette County averages can't show:
We read public map data around Sublette County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Sublette County average
How we know this about Sublette 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 Sublette County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Sublette County
When does frost risk typically end in Sublette County?
The last hard freeze (28°F) in Sublette County typically lands around Jun 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 Jun 30.
How long is the growing season in Sublette County?
Measured between 28°F hard freezes, Sublette County sees about 89 frost-free days — roughly Jun 9 through Sep 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 30 to Aug 23, about 54 days.
Is the soil safe to grow vegetables in Sublette County?
The federal record around Sublette County is a meaningful one — 260 documented sites, mostly Nitrate entries (164), the nearest Underground Storage Tanks record about 5.9 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.
How do gardeners stretch the season in Sublette County?
With about 89 frost-free days between hard freezes, Sublette County 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 117 to 145 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the Jun 9 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Sublette County's scale — its 4b band and its 89-day season. Your yard writes its own version of Sublette 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 Sublette County’s own scale
8 of the readings below were taken at Sublette County's own scale — its own ~89-day span between 28°F freezes, the 3 most extensive soil series mapped here and 260 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Sublette County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Sublette County's own 28°F hard-freeze dates and its ~89-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Sublette CountyUSDA NRCS SSURGO
- 260 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 5.9 miles outFederal environmental registers
- Sublette County's boundary and the 3,127,345 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~89-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Sublette County spans, Wyoming Basin the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Sublette 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 Sublette County — the ~89 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 Sublette County's 3,127,345 acreswhy one lot differs from the next →
- Which of those 260 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 Sublette Countyread your own land →