Frost Report

All states Idaho

Frost dates for Rupert, 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 6

typical year

Safe to plant

May 22

frost is over in 9 of 10 years

First fall frost

October 6

typical year

Growing season

151 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 8 – 22 –
Spinach – Mar 25 – Apr 15 Aug 11 – 25
Lettuce – Apr 8 – 29 Aug 11 – 25
Radishes – Apr 8 – May 20 Aug 25 – Sep 8
Onions – Apr 8 – 22 –
Potatoes – Apr 15 – 29 –
Carrots – Apr 15 – May 6 Jul 14 – 28
Beets – Apr 8 – 22 Jul 28 – Aug 11
Kale Feb 25 – Mar 11 Apr 8 – 22 Jul 28 – Aug 11
Broccoli Feb 25 – Mar 11 Apr 22 – May 6 Jul 28 – Aug 11
Cabbage Feb 11 – 25 Apr 8 – 22 Jul 28 – Aug 11
Garlic – – Aug 25 – Sep 15
Warm-season crops
Tomatoes Mar 27 – Apr 10 May 22 – Jun 5 –
Peppers Mar 20 – Apr 3 May 29 – Jun 12 –
Cucumbers – May 22 – Jun 12 –
Zucchini – May 22 – Jun 19 –
Pumpkins – May 22 – Jun 12 –
Green beans – May 22 – Jul 28 –
Sweet corn – May 22 – Jun 19 –
Basil Apr 17 – May 1 May 29 – Jun 5 –

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 22May 6April 23
Fall frost before September 22October 6October 19

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 April 22 (May 7 in a late year), and the first one in fall around October 18.

Towns that use these dates

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

Rupert, Paul

Where these dates come from

NOAA weather station PAUL 1ENE, ID US (USC00106877), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 3 miles:

83347

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