When is the last frost in Billings, MT?

The average (50% probability) last spring frost in Billings is May 4, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until May 18.

When is the first frost in Billings?

The average first fall frost in Billings is October 7, with a growing season of about 156 days.

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Billings, Montana frost dates

Average last spring frost: May 4. Average first fall frost: October 7. That gives a growing season of about 156 days. For frost-tender plants, a safer planting date is May 18, after which a freeze happens in only 1 year in 10.

Last frost (50%)

May 4

1-in-10 risk after May 18

First frost (50%)

Oct 7

1-in-10 risk before Sep 26

Growing season

156 days

median frost-free days

Hard freeze (28°F)

Apr 21

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	April 20	October 21
70%	April 29	October 14
50%	May 4	October 7
30%	May 10	October 1
10%	May 18	September 26

Read the spring column like this: there is a 10% chance of a 32°F freeze after May 18. These are NOAA probabilities for the Billings Logan International Airport weather station (USW00024033, elevation 1092 m), 1991–2020.

Billings vegetable planting calendar

Dates count from the 50% last-frost date (May 4). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (May 18) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Apr 13	May 11 (usually sown directly in the garden)
Broccoli	Feb 23	Apr 6
Brussels sprouts	Feb 23	Apr 6
Cabbage	Feb 16	Mar 30
Cauliflower	Mar 9	Apr 20
Sweet corn	Apr 6	May 4 (usually sown directly in the garden)
Cucumbers	Apr 20	May 11
Kale	Feb 16	Mar 30
Leeks	Jan 19	Mar 30
Lettuce	Mar 16	Apr 20
Melons	Apr 27	May 18
Onions	Jan 12	Mar 23 (from seed; sets and transplants go out at the same time)
Peas	Mar 9	Apr 6 (usually sown directly in the garden)
Peppers	Mar 23	May 18
Squash	Apr 27	May 18
Tomatoes	Mar 9	May 4

Offsets from Oregon State University Extension's seed-starting table. "Plant out" means transplant, or sow directly for crops usually grown from seed.

Fall frost and season extension

The first fall freeze usually arrives around October 7. There's a 1-in-10 chance it comes before September 26. Harvest tender crops such as basil, tomatoes, peppers and squash before then, or cover them on cold nights. Cool-season crops like kale, cabbage and Brussels sprouts handle light frost, and often taste sweeter after it. A hard freeze (28°F) typically comes around October 16.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Missoula, MT	May 16	Sep 26	~447 km
Rapid City, SD	May 12	Oct 1	~468 km
Cheyenne, WY	May 12	Oct 1	~592 km
Bismarck, ND	May 14	Sep 27	~612 km
Salt Lake City, UT	Apr 8	Oct 31	~618 km
Boise, ID	Apr 24	Oct 21	~645 km

More: all Montana frost dates