Guernsey, 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.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Guernsey, 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 Guernsey 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 Guernsey — soil, climate, flood, and parcel records. How we handle your address.
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Guernsey — the short answer
Guernsey, Wyoming: USDA zone 5a, about 153 days between hard freezes, across 654 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~153
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 654 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 Guernsey's average, not your lot's — a low corner or a tree line moves it. Against Guernsey's 153-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Guernsey
Each reading below is measured for Guernsey itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGuernsey runs about 153 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
MeasuredGuernsey 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 Guernsey is in
Guernsey sits in the High Plains — EPA Level III, inside the wider Great Plains. That is read at Guernsey's own centroid rather than borrowed from Platte County.
What Grows in Guernsey
Every plant below cleared Guernsey's own zone 5a and its 153-day season. Each card opens that plant's Wyoming profile. How we score.
Is it too late to plant in Guernsey?
Almost never — the real question is what to plant next. 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 6 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Guernsey
Closest first, within ~10 miles of Guernsey. Listing isn't leaking, and distance isn't exposure.
- PLATTE COUNTY SCHOOL DISTRICT #2Brownfields · 800 ft
- TOWN OF GUERNSEY MAINTENANCE FACILITYBrownfields · 1100 ft
- U.S. ARMY CAMP GUERNSEY TRAINING AREASToxics Release Inventory · 1200 ft
- Valley MotorsUnderground Storage Tanks · 1500 ft
- Good To Go Store #21Underground Storage Tanks · 1800 ft
- Guernsey State ParkUnderground Storage Tanks · 1800 ft
- Larson MotorsUnderground Storage Tanks · 1900 ft
- Guernsey Jack and Jill Food CenterUnderground Storage Tanks · 2000 ft
- ChoppersUnderground Storage Tanks · 2000 ft
- Guernsey MartUnderground Storage Tanks · 2100 ft
- Town of GuernseyUnderground Storage Tanks · 2200 ft
- Courtesy Service Company, Inc.Underground Storage Tanks · 2200 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Guernsey'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 Guernsey.
Total Sites
48
within ~10 miles of Guernsey
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Guernsey
Severity Distribution
within ~10 miles of Guernsey
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Guernsey, Mining runs higher than the national average — 8 sites within ~10 miles of Guernsey. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Guernsey
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 Guernsey average
Your land is one point inside Guernsey
Everything above resolves to Guernsey as a whole — one PHZM band and one 28°F frost record, read across 654 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 Guernsey Average
Guernsey Average
- ●USDA Zones 5a, averaged across Guernsey
- ●One soil character for all of Guernsey
- ●Frost dates read at Guernsey's scale: May 6 to Oct 6
YOUR Parcel
- ✓Your exact zone, not Guernsey's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Guernsey
Pull a site-specific report for your exact address in Guernsey, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Guernsey averages can't show:
We read public map data around Guernsey — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Guernsey average
How we know this about Guernsey
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 Guernsey’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 Guernsey
When does frost risk typically end in Guernsey?
The last hard freeze (28°F) in Guernsey 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.
When is the first frost in Guernsey?
The first hard freeze (28°F) in Guernsey typically arrives around Oct 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 22, so the watching starts about Sep 6 — about 153 days after the spring freeze cleared.
How long is the growing season in Guernsey?
Measured between 28°F hard freezes, Guernsey sees about 153 frost-free days — roughly May 6 through Oct 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 22, about 118 days.
Is the soil safe to grow vegetables in Guernsey?
The federal record around Guernsey is a meaningful one — 48 documented sites, mostly Underground Storage Tanks entries (16), the nearest Brownfields record about 0.2 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 I protect my plants from frost in Guernsey?
From about Sep 6 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 6 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Guernsey's scale — its 5a band and its 153-day season. Your yard writes its own version of Guernsey'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 Guernsey’s own scale
6 of the readings below were taken at Guernsey's own scale — its own ~153-day season between 28°F freezes, the 654 acres it covers and 48 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Guernsey's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Guernsey's own 28°F hard-freeze dates, about May 6 and Oct 6 and the ~153-day span between themNOAA 1991–2020 Climate Normals
- 48 documented contamination sites on the federal record near Guernsey, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Guernsey's boundary and the 654 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~153-day seasonGrowable Ground crop-matching engine
- The ecoregion at Guernsey's own centroid, the High PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Guernsey's 654 acres read through its county's SSURGO summaryfrom Platte County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Platte 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 Platte County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Guernsey's 654 acreswhy one lot differs from the next →
- Which side of Guernsey you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 654 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.2 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 Guernsey-wide figureread your own land →
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