Jeffrey City, Wyoming, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Well-matched crops include cabbage, cranberry, cilantro, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Jeffrey City, 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 Jeffrey City 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 Jeffrey City — soil, climate, flood, and parcel records. How we handle your address.
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Jeffrey City — the short answer
Jeffrey City, Wyoming: USDA zone 4b, about 131 days between hard freezes, across 18K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~131
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 18K 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 4b is Jeffrey City's average, not your lot's — a low corner or a tree line moves it. Against Jeffrey City's 131-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Jeffrey City
Each reading below is measured for Jeffrey City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredJeffrey City runs about 131 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
MeasuredJeffrey City 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 Jeffrey City is in
Jeffrey City sits in the Wyoming Basin — EPA Level III, inside the wider North American Deserts. That is read at Jeffrey City's own centroid rather than borrowed from Fremont County.
What Grows in Jeffrey City
Every plant below cleared Jeffrey City's own zone 4b and its 131-day season. Each card opens that plant's Wyoming profile. How we score.
Is it too late to plant in Jeffrey City?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 24 — 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's on the federal record near Jeffrey City
Closest first, within ~10 miles of Jeffrey City. Listing isn't leaking, and distance isn't exposure.
- JEFFREY CITY SCHOOLBrownfields · 0.7 mi
- Split Rock CaféUnderground Storage Tanks · 0.8 mi
- Muddy GapUnderground Storage Tanks · 0.8 mi
- Split Rock MillUnderground Storage Tanks · 0.8 mi
- Crooks GapUnderground Storage Tanks · 0.8 mi
- Hot Springs REA, Inc.Underground Storage Tanks · 1.7 mi
- CREATIVE ENERGIESBrownfields · 2.2 mi
- Skorcz ElectricUnderground Storage Tanks · 2.3 mi
- Crooks Gap OilfieldUnderground Storage Tanks · 5.9 mi
- GREEN MOUNTAIN GROUP (TRONOX)Superfund · 6.4 mi
- 29-091-13cab01Nitrate · 8.0 mi
- 30-093-21ddb01Nitrate · 8.1 mi
Measured from Jeffrey City'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 Jeffrey City.
Total Sites
14
within ~10 miles of Jeffrey City
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Jeffrey City
Severity Distribution
within ~10 miles of Jeffrey City
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Jeffrey City
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 Jeffrey City average
Your land is one point inside Jeffrey City
Everything above resolves to Jeffrey City as a whole — one PHZM band and one 28°F frost record, read across 18K 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 Jeffrey City Average
Jeffrey City Average
- ●USDA Zones 4b, averaged across Jeffrey City
- ●One soil character for all of Jeffrey City
- ●Frost dates read at Jeffrey City's scale: May 16 to Sep 24
YOUR Parcel
- ✓Your exact zone, not Jeffrey City's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Jeffrey City
Pull a site-specific report for your exact address in Jeffrey City, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Jeffrey City averages can't show:
We read public map data around Jeffrey City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Jeffrey City average
How we know this about Jeffrey City
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 Jeffrey City’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 Jeffrey City
When does frost risk typically end in Jeffrey City?
The last hard freeze (28°F) in Jeffrey City typically lands around May 16, 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 6.
When is the first frost in Jeffrey City?
The first hard freeze (28°F) in Jeffrey City typically arrives around Sep 24, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 10, so the watching starts about Aug 25 — about 131 days after the spring freeze cleared.
How long is the growing season in Jeffrey City?
Measured between 28°F hard freezes, Jeffrey City sees about 131 frost-free days — roughly May 16 through Sep 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 6 to Sep 10, about 96 days.
Is the soil safe to grow vegetables in Jeffrey City?
The federal record around Jeffrey City is a meaningful one — 14 documented sites, mostly Underground Storage Tanks entries (7), the nearest Brownfields record about 0.7 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 Jeffrey City?
With about 131 frost-free days between hard freezes, Jeffrey City 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 159 to 187 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 16 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Jeffrey City's scale — its 4b band and its 131-day season. Your yard writes its own version of Jeffrey City'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 Jeffrey City’s own scale
6 of the readings below were taken at Jeffrey City's own scale — its own ~131-day season between 28°F freezes, the 18,134 acres it covers and 14 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Jeffrey City's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Jeffrey City's own 28°F hard-freeze dates, about May 16 and Sep 24 and the ~131-day span between themNOAA 1991–2020 Climate Normals
- 14 documented contamination sites on the federal record near Jeffrey City, the closest Brownfields record about 0.7 miles out from the town centreFederal environmental registers
- Jeffrey City's boundary and the 18,134 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~131-day seasonGrowable Ground crop-matching engine
- The ecoregion at Jeffrey City's own centroid, the Wyoming BasinUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Jeffrey City's 18,134 acres read through its county's SSURGO summaryfrom Fremont County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Fremont 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 Fremont County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Jeffrey City's 18,134 acreswhy one lot differs from the next →
- Which side of Jeffrey City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 18,134 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.7 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 Jeffrey City-wide figureread your own land →
More in Wyoming
Wider growing context
What grows across WyomingJeffrey City sits outside our named growing regions, so Wyoming as a whole is its closest context here.
Nearby growing guides