When to plant sweet corn in Cheyenne, Wyoming

May 28 – June 11

Direct-sow outdoors · typical Cheyenne year

Climate basis: NOAA station Cheyenne Wfo, WY (USC00481676), 7 mi (12 km) from downtown Cheyenne (ZCTA 82001 centroid), elevation 6119 ft, on the 1991–2020 climate normals. Direct-sow sweet corn from approximately the dates above, anchored to the median last spring 32°F freeze (May 14). One year in ten still freezes after May 28.

Last spring freezeMay 141-in-10 after May 28
First fall freezeOctober 11-in-10 before Sep 17
Frost-free season139 daysmedian at 32°F
Hard freeze, 28°May 3Oct 10kills even hardy greens
USDA zone5b-15 to -10°F winter low not frost timing

The Cheyenne year

Direct-sow outdoorsMay 28 – Jun 11
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 28
Sweet corn in Cheyenne · freeze context from Cheyenne Wfo, WY, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

May 28 – Jun 11

UGA: wait until at least two weeks after the last average killing frost. Purdue lists corn as tender (after last frost) and UNH keys sowing to 60°F soil; the later UGA rule is used. Anchored to the median last spring freeze (May 14). University of Georgia Cooperative Extension · Purdue University Extension · University of New Hampshire Extension

Start seeds indoors

Not calculated

The cited guides time sweet corn by direct seeding only.

Transplant outdoors

Not calculated

The cited extension guides do not time an outdoor transplanting window for this crop.

Fall planting

Not calculated

No source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.

Variety assumption: Assumes a mid-season hybrid (about 70–85 days; Penn State lists 80).

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:
Crop rule sources (3)

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