Generally — Most Areas
winter melon (zones 5-12) suits most of Wyoming (3b-6a) — zones 5-6 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
Wyoming spans zones 3b-6a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score winter melon against your land's actual soil, sun, and frost.
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Zone Comparison
Winter Melon Needs
- USDA Zones: 5-12
- Frost-Free Days: 80+
- Sun: Full Sun
- Mature size: 12 ft tall
- Picking window: ~14 days of harvest
- Drought tolerance: Low
Wyoming Has
- USDA Zones: 3b-6a
- Last Hard Freeze (28°F): May 4 - May 13
- First Hard Freeze (28°F): Sep 30 - Oct 7
- Annual Rainfall: 6-20 inches
- Common Soils: Sandy loam, Clay, Alkaline
Plant Zone Range (zones 5-12)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Winter Melon in Wyoming
The frost window
Across Wyoming, the last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 140-day window you can count on — up to 156 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Frost tenderness
Winter Melon is frost-tender — its listed minimum temperature is 53.6°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
When to start the seed
Those dates are when winter melon goes out, not when it starts. It is sown under cover about 3 weeks ahead, so counting back from Wyoming's late-side last freeze of May 13 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Days to maturity vs. the window
At 120 days to maturity (USDA PLANTS Database), one crop fits Wyoming's 140-day dependable window with 20 days of margin — plant at the front of the window to keep that cushion.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says winter melon survives winter in part of Wyoming, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Winter Melon wants 80+ frost-free days; a typical Wyoming site sees ~151 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Winter Melon needs ~3000 GDD (base 50°F) to ripen. The state median runs ~1866 GDD (from PRISM 1991-2020 climate normals), so Wyoming's typical season runs short on heat — pick a south-facing site and consider season extension.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Winter Melon likes near-neutral soil (pH 5-7.5). That's the common-ground band across Wyoming's sandy loam and clay — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.6 and 6.8 — worth knowing before you decide whether a Wyoming soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Wyoming site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH and drainage requirements from USDA PLANTS Database. Wyoming soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Winter Melon in Wyoming — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 5-12 (USDA PLANTS Database)
- State Zones: 3b-6a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about May 4 - May 13 to Sep 30 - Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020)
- Days to Maturity: 120 days
What Else to Consider for Winter Melon in Wyoming
Zone compatibility tells you about winter cold survival — but Wyoming growers also need to think about:
Extremely short growing season (60-90 frost-free days)
Very low rainfall requires irrigation
Persistent high winds desiccate and damage plants
What to actually do about these — and the constraints that apply to every Wyoming grower, not just winter melon — is covered on the Wyoming growing guide.
Timing shifts within Wyoming
Winter Melon needs about 80 days of frost-free season to complete its cycle. 22 of Wyoming’s 23 counties give it that outright. The tightest that does is Sublette County at 89 frost-free days — 9 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Wyoming’s 23 counties the frost-free season runs from 79 days in Teton County to 166 days in Big Horn County — a spread of 87 days, which is why a single statewide planting date misleads. The median Wyoming county sees 151 frost-free days, leaving winter melon about 71 days of slack on a typical parcel — room for a second sowing where the season runs long.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Winter Melon's 80-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in Wyoming Fits Best
Even within Wyoming's zones 3b-6a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for winter melon (USDA PHZM 2023):
Pollinator + Wildlife Value
Winter Melon draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, winter melon can only work that bloom inside Wyoming's frost window — roughly 151 days, opening after the last 28°F freeze (May 4 - May 13) and closing at the first (Sep 30 - Oct 7), per NOAA Regional Climate Centers ACIS, 1991-2020.
Wyoming Cooperative Extension
For Wyoming-specific cultivar recommendations, planting calendars, and pest pressure for winter melon, the canonical source is University of Wyoming Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Winter Melon native to Wyoming?
No — the USDA PLANTS Database lists Winter Melon as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.
Looking for plants that belong here? The Wyoming growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Winter Melon in Wyoming
When can I plant Winter Melon in Wyoming?
Wyoming's last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Winter Melon is frost-tender — its listed minimum temperature is 53.6°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Winter Melon mature before first frost in Wyoming?
Yes — Winter Melon matures in 120 days (USDA PLANTS Database), and Wyoming's dependable hard-freeze-free window runs 140 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 20 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Winter Melon grown in across Wyoming?
Wyoming spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Winter Melon carries a range of zones 5-12, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Wyoming site have?
A typical Wyoming site sees ~151 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Winter Melon needs 80+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Winter Melon native to Wyoming?
No — the USDA PLANTS Database lists Winter Melon as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.
How should I amend the soil for Winter Melon in Wyoming?
Winter Melon prefers pH 5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Wyoming soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Winter Melon actually grow on my specific land in Wyoming?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores winter melon against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Wyoming
State-level data is a sketch. Your Growable Ground report scores winter melon against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Wyoming winter melon averages can't show:
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Growing guides for winter melon
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