Afton, Wyoming, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include zucchini, cranberry, cilantro, and okra; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Afton, 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 Afton 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 Afton — soil, climate, flood, and parcel records. How we handle your address.
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Afton — the short answer
Afton, Wyoming: USDA zone 4b, about 109 days between hard freezes, across 3K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~109
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 3K 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 Afton's average, not your lot's — a low corner or a tree line moves it. Against Afton's 109-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Afton
Each reading below is measured for Afton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAfton runs about 109 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
MeasuredAfton 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 Afton is in
Afton sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Afton's own centroid, and it is not what its county reads: Lincoln County is mostly Wyoming Basin. The wider page above you is answering a different question about different ground.
What Grows in Afton
Every plant below cleared Afton's own zone 4b and its 109-day season. Each card opens that plant's Wyoming profile. How we score.
Is it too late to plant in Afton?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around May 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 15 — 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 Afton
Closest first, within ~10 miles of Afton. Listing isn't leaking, and distance isn't exposure.
- Maverik Country Store # 355Underground Storage Tanks · 400 ft
- Afton Tri-Mart #1202Underground Storage Tanks · 400 ft
- Bank of Star ValleyUnderground Storage Tanks · 450 ft
- Texaco (Abandoned)Underground Storage Tanks · 550 ft
- Evan WaltonUnderground Storage Tanks · 1300 ft
- Lincoln County School District #2Underground Storage Tanks · 1400 ft
- Kum and Go #952Underground Storage Tanks · 1500 ft
- Don WoodUnderground Storage Tanks · 2100 ft
- Salt River Oil and Motor CompanyUnderground Storage Tanks · 2300 ft
- Private ResidenceUnderground Storage Tanks · 2300 ft
- Peavler EnterprisesUnderground Storage Tanks · 2400 ft
- AVIAT AIRCRAFT, INCBrownfields · 0.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Afton'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 Afton.
Total Sites
90
within ~10 miles of Afton
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Afton
Severity Distribution
within ~10 miles of Afton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Afton, Nitrate runs higher than the national average — 40 sites within ~10 miles of Afton. 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 Afton
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 Afton average
Your land is one point inside Afton
Everything above resolves to Afton as a whole — one PHZM band and one 28°F frost record, read across 3K 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 Afton Average
Afton Average
- ●USDA Zones 4b, averaged across Afton
- ●One soil character for all of Afton
- ●Frost dates read at Afton's scale: May 29 to Sep 15
YOUR Parcel
- ✓Your exact zone, not Afton's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Afton
Pull a site-specific report for your exact address in Afton, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Afton averages can't show:
We read public map data around Afton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Afton average
How we know this about Afton
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 Afton’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 Afton
When does frost risk typically end in Afton?
The last hard freeze (28°F) in Afton typically lands around May 29, 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 19.
When is the first frost in Afton?
The first hard freeze (28°F) in Afton typically arrives around Sep 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 1, so the watching starts about Aug 16 — about 109 days after the spring freeze cleared.
How long is the growing season in Afton?
Measured between 28°F hard freezes, Afton sees about 109 frost-free days — roughly May 29 through Sep 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 19 to Sep 1, about 74 days.
Is the soil safe to grow vegetables in Afton?
The federal record around Afton is a meaningful one — 90 documented sites, mostly Nitrate entries (40), the nearest Underground Storage Tanks record under a tenth of a mile 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 Afton?
With about 109 frost-free days between hard freezes, Afton 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 137 to 165 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 29 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Afton's scale — its 4b band and its 109-day season. Your yard writes its own version of Afton'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 Afton’s own scale
6 of the readings below were taken at Afton's own scale — its own ~109-day season between 28°F freezes, the 2,857 acres it covers and 90 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Afton's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Afton's own 28°F hard-freeze dates, about May 29 and Sep 15 and the ~109-day span between themNOAA 1991–2020 Climate Normals
- 90 documented contamination sites on the federal record near Afton, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Afton's boundary and the 2,857 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~109-day seasonGrowable Ground crop-matching engine
- Afton sits in the Middle Rockies — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Afton's 2,857 acres read through its county's SSURGO summaryfrom Lincoln County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lincoln 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 Lincoln County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Afton's 2,857 acreswhy one lot differs from the next →
- Which side of Afton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,857 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Afton-wide figureread your own land →
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