Frost Report

All states Montana

Frost dates for Divide, MT

When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.

Last spring frost

June 10

typical year

Safe to plant

July 2

frost is over in 9 of 10 years

First fall frost

September 7

typical year

Growing season

85 days

frost-free, typical year

When to plant

Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.

CropStart indoorsPlant outsideFall planting
Cool-season crops
Peas – May 13 – 27 –
Spinach – Apr 29 – May 20 Jul 13 – 27
Lettuce – May 13 – Jun 3 Jul 13 – 27
Radishes – May 13 – Jun 24 Jul 27 – Aug 10
Onions – May 13 – 27 –
Potatoes Season usually too short. Try a quick variety or row covers.
Carrots – May 20 – Jun 10 Jun 15 – 29
Beets – May 13 – 27 Jun 29 – Jul 13
Kale Apr 1 – 15 May 13 – 27 Jun 29 – Jul 13
Broccoli Apr 1 – 15 May 27 – Jun 10 Jun 29 – Jul 13
Cabbage Mar 18 – Apr 1 May 13 – 27 Jun 29 – Jul 13
Garlic – – Jul 27 – Aug 17
Warm-season crops
Tomatoes Season usually too short. Try a quick variety or row covers.
Peppers Season usually too short. Try a quick variety or row covers.
Cucumbers – Jul 2 – 23 –
Zucchini – Jul 2 – 30 –
Pumpkins Season usually too short. Try a quick variety or row covers.
Green beans Season usually too short. Try a quick variety or row covers.
Sweet corn Season usually too short. Try a quick variety or row covers.
Basil May 28 – Jun 11 Jul 9 – 16 –

Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.

The year at a glance

Start indoors Plant outside Fall planting

The chance of frost, by date

1 year in 10Half of years9 years in 10
Spring frost after July 2June 10May 23
Fall frost before August 24September 7September 20

Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.

Hard freeze (28°F)

A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around May 21 (June 9 in a late year), and the first one in fall around September 19.

Where these dates come from

NOAA weather station DIVIDE, MT US (USC00242421), 1991–2020 climate normals. It's the nearest station for 3 zip codes, all within 18 miles:

59727, 59732, 59743

Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.