Frost Report

All states Idaho

Frost dates for Sugar City, 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 29

typical year

Safe to plant

June 18

frost is over in 9 of 10 years

First fall frost

September 13

typical year

Growing season

106 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 1 – 15 –
Spinach – Apr 17 – May 8 Jul 19 – Aug 2
Lettuce – May 1 – 22 Jul 19 – Aug 2
Radishes – May 1 – Jun 12 Aug 2 – 16
Onions – May 1 – 15 –
Potatoes Season usually too short. Try a quick variety or row covers.
Carrots – May 8 – 29 Jun 21 – Jul 5
Beets – May 1 – 15 Jul 5 – 19
Kale Mar 20 – Apr 3 May 1 – 15 Jul 5 – 19
Broccoli Mar 20 – Apr 3 May 15 – 29 Jul 5 – 19
Cabbage Mar 6 – 20 May 1 – 15 Jul 5 – 19
Garlic – – Aug 2 – 23
Warm-season crops
Tomatoes Apr 23 – May 7 Jun 18 – Jul 2 –
Peppers Apr 16 – 30 Jun 25 – Jul 9 –
Cucumbers – Jun 18 – Jul 9 –
Zucchini – Jun 18 – Jul 16 –
Pumpkins Season usually too short. Try a quick variety or row covers.
Green beans – Jun 18 – Jul 5 –
Sweet corn – Jun 18 – Jul 16 –
Basil May 14 – 28 Jun 25 – Jul 2 –

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 18May 29May 12
Fall frost before August 30September 13October 1

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 9 (May 27 in a late year), and the first one in fall around September 25.

Towns that use these dates

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

Sugar City, Teton

Where these dates come from

NOAA weather station SUGAR CITY, ID US (USC00108818), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 5 miles:

83448, 83451

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