Frost Report

All states Idaho

Frost dates for Mackay, 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 14

typical year

Safe to plant

June 30

frost is over in 9 of 10 years

First fall frost

September 8

typical year

Growing season

86 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 17 – 31 –
Spinach – May 3 – 24 Jul 14 – 28
Lettuce – May 17 – Jun 7 Jul 14 – 28
Radishes – May 17 – Jun 28 Jul 28 – Aug 11
Onions – May 17 – 31 –
Potatoes Season usually too short. Try a quick variety or row covers.
Carrots – May 24 – Jun 14 Jun 16 – 30
Beets – May 17 – 31 Jun 30 – Jul 14
Kale Apr 5 – 19 May 17 – 31 Jun 30 – Jul 14
Broccoli Apr 5 – 19 May 31 – Jun 14 Jun 30 – Jul 14
Cabbage Mar 22 – Apr 5 May 17 – 31 Jun 30 – Jul 14
Garlic – – Jul 28 – Aug 18
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 – Jun 30 – Jul 21 –
Zucchini – Jun 30 – Jul 28 –
Pumpkins Season usually too short. Try a quick variety or row covers.
Green beans – Jun 30 –
Sweet corn Season usually too short. Try a quick variety or row covers.
Basil May 26 – Jun 9 Jul 7 – 14 –

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 30June 14May 27
Fall frost before August 26September 8September 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 24 (June 15 in a late year), and the first one in fall around September 20.

Towns that use these dates

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

Mackay

Where these dates come from

NOAA weather station CHILLY BARTON FLAT, ID US (USC00101671), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 6 miles:

83251

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