Frost Report

All states Idaho

Frost dates for Shelley, ID

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 23

typical year

Safe to plant

June 13

frost is over in 9 of 10 years

First fall frost

September 20

typical year

Growing season

114 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 25 – May 9 –
Spinach – Apr 11 – May 2 Jul 26 – Aug 9
Lettuce – Apr 25 – May 16 Jul 26 – Aug 9
Radishes – Apr 25 – Jun 6 Aug 9 – 23
Onions – Apr 25 – May 9 –
Potatoes – May 2 – 16 –
Carrots – May 2 – 23 Jun 28 – Jul 12
Beets – Apr 25 – May 9 Jul 12 – 26
Kale Mar 14 – 28 Apr 25 – May 9 Jul 12 – 26
Broccoli Mar 14 – 28 May 9 – 23 Jul 12 – 26
Cabbage Feb 28 – Mar 14 Apr 25 – May 9 Jul 12 – 26
Garlic – – Aug 9 – 30
Warm-season crops
Tomatoes Apr 18 – May 2 Jun 13 – 27 –
Peppers Apr 11 – 25 Jun 20 – Jul 4 –
Cucumbers – Jun 13 – Jul 4 –
Zucchini – Jun 13 – Jul 11 –
Pumpkins Season usually too short. Try a quick variety or row covers.
Green beans – Jun 13 – Jul 12 –
Sweet corn – Jun 13 – Jul 11 –
Basil May 9 – 23 Jun 20 – 27 –

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 June 13May 23May 7
Fall frost before September 1September 20October 4

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 7 (May 23 in a late year), and the first one in fall around October 2.

Towns that use these dates

This is the nearest NOAA station with frost records for 1 town.

Shelley

Where these dates come from

NOAA weather station IDAHO FALLS FANNING FLD, ID US (USW00024145), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 12 miles:

83274, 83402

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