When to plant southern pea in Billings, Montana

May 10 – May 24

Direct-sow outdoors · typical Billings year

Climate basis: NOAA station Billings Wtp, MT (USC00240802), 13 mi (21 km) from downtown Billings (ZCTA 59101 centroid), elevation 3097 ft, on the 1991–2020 climate normals. Direct-sow southern pea from approximately the dates above, anchored to the median last spring 32°F freeze (May 10). One year in ten still freezes after May 24.

Last spring freezeMay 101-in-10 after May 24
First fall freezeOctober 11-in-10 before Sep 19
Frost-free season142 daysmedian at 32°F
Hard freeze, 28°Apr 27Oct 12kills even hardy greens
USDA zone5a-20 to -15°F winter low not frost timing

The Billings year

Direct-sow outdoorsMay 10 – May 24
Fall plantingJul 18 – Jul 28
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 24
Southern Pea in Billings · freeze context from Billings Wtp, MT, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

May 10 – May 24

Maryland Extension says to wait until all danger of frost is passed, Alabama Extension says to plant after any danger of frost has passed, and Texas A&M's crop guide lists the optimum time as soil above 65°F with danger of frost over; all three agree on the last-frost date, so the point rule opens the window at the anchor and runs 14 days. Anchored to the median last spring freeze (May 10). Alabama Cooperative Extension System · Texas A&M AgriLife Extension

Fall planting

Jul 18 – Jul 28

Arkansas Extension gives an explicit frost-anchored fall range — plant about 65 to 75 days prior to the average frost date — which encodes directly as 75 to 65 days before the first fall freeze; it is the only source in this set that states fall timing relative to frost rather than by calendar month. Anchored to the median first fall freeze (Oct 1). University of Maryland Extension · Alabama Cooperative Extension System · University of Arkansas Cooperative Extension Service · Texas A&M AgriLife Extension

Variety assumption: Assumes a standard 60–70 day bush or semi-vining southern pea; the fall window is Arkansas' allowance for the crop to set and fill pods before the first freeze.

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 (4)

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