When to plant pumpkins in Billings, Montana

May 30 – June 13

Transplant 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. Transplant pumpkins outdoors 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 season≈ 142 daysmedian at 32°F

Hard freeze, 28°Apr 27 – Oct 12kills even hardy greens

USDA zone5a-20 to -15°F winter low — not frost timing

The Billings year

Start seeds indoorsApr 18 – May 2

Transplant outdoorsMay 30 – Jun 13

Direct-sow outdoorsMay 30 – Jun 13

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to May 24

Pumpkins in Billings · freeze context from Billings Wtp, MT, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Apr 18 – May 2

Sow in pots 4–6 weeks before the outdoor window opens (Missouri G6570: 4–6 weeks). Anchored to the median last spring freeze (May 10). University of Missouri Extension

Transplant outdoors

May 30 – Jun 13

Same outdoor timing as direct seeding, using pot-grown transplants. Anchored to the median last spring freeze (May 10). Penn State Extension (York County Master Gardeners) · Purdue University Extension · University of Missouri Extension

Direct-sow outdoors

May 30 – Jun 13

Purdue: very tender — at least two weeks after the last frost; Penn State's earliest sowing May 21 (+20 days) is the later start and is used. Anchored to the median last spring freeze (May 10). Penn State Extension (York County Master Gardeners) · Purdue University Extension

Variety assumption: Assumes an average carving variety (about 100–115 days; Penn State lists 110). For Halloween pumpkins, sow toward the start of the window.

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)

University of Missouri Extension: Starting Plants Indoors from Seeds (G6570) (accessed 2026-07-24)
Weeks needed to grow vegetable transplants indoors (Table 2).
Penn State Extension (York County Master Gardeners): Vegetable Seed Planting Guide (accessed 2026-07-24)
Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.

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