Frost Report

All states Montana

Frost dates for Bridger, 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

May 14

typical year

Safe to plant

May 30

frost is over in 9 of 10 years

First fall frost

September 24

typical year

Growing season

129 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 – Apr 16 – 30 –
Spinach – Apr 2 – 23 Jul 30 – Aug 13
Lettuce – Apr 16 – May 7 Jul 30 – Aug 13
Radishes – Apr 16 – May 28 Aug 13 – 27
Onions – Apr 16 – 30 –
Potatoes – Apr 23 – May 7 –
Carrots – Apr 23 – May 14 Jul 2 – 16
Beets – Apr 16 – 30 Jul 16 – 30
Kale Mar 5 – 19 Apr 16 – 30 Jul 16 – 30
Broccoli Mar 5 – 19 Apr 30 – May 14 Jul 16 – 30
Cabbage Feb 19 – Mar 5 Apr 16 – 30 Jul 16 – 30
Garlic – – Aug 13 – Sep 3
Warm-season crops
Tomatoes Apr 4 – 18 May 30 – Jun 13 –
Peppers Mar 28 – Apr 11 Jun 6 – 20 –
Cucumbers – May 30 – Jun 20 –
Zucchini – May 30 – Jun 27 –
Pumpkins – May 30 – Jun 20 –
Green beans – May 30 – Jul 16 –
Sweet corn – May 30 – Jun 27 –
Basil Apr 25 – May 9 Jun 6 – 13 –

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 May 30May 14May 2
Fall frost before September 7September 24October 7

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 1 (May 13 in a late year), and the first one in fall around October 4.

Towns that use these dates

This is the nearest NOAA station with frost records for 2 towns.

Bridger, Fromberg

Where these dates come from

NOAA weather station BRIDGER 2 N, MT US (USC00241102), 1991–2020 climate normals. It's the nearest station for 3 zip codes, all within 19 miles:

59014, 59029, 59066

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