Frost Report

All states Idaho

Frost dates for Hill 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

June 16

typical year

Safe to plant

July 3

frost is over in 9 of 10 years

First fall frost

September 6

typical year

Growing season

80 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 19 – Jun 2 –
Spinach – May 5 – 26 Jul 12 – 26
Lettuce – May 19 – Jun 9 Jul 12 – 26
Radishes – May 19 – Jun 30 Jul 26 – Aug 9
Onions – May 19 – Jun 2 –
Potatoes Season usually too short. Try a quick variety or row covers.
Carrots – May 26 – Jun 16 Jun 14 – 28
Beets – May 19 – Jun 2 Jun 28 – Jul 12
Kale Apr 7 – 21 May 19 – Jun 2 Jun 28 – Jul 12
Broccoli Apr 7 – 21 Jun 2 – 16 Jun 28 – Jul 12
Cabbage Mar 24 – Apr 7 May 19 – Jun 2 Jun 28 – Jul 12
Garlic – – Jul 26 – Aug 16
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 3 – 24 –
Zucchini – Jul 3 – 31 –
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 29 – Jun 12 Jul 10 – 17 –

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 3June 16May 31
Fall frost before August 20September 6September 22

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 30 (June 21 in a late year), and the first one in fall around September 18.

Where these dates come from

NOAA weather station HILL CITY 1 W, ID US (USC00104268), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 7 miles:

83322, 83337

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