Frost Report

All states Utah

Frost dates for Dewey, UT

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

April 27

typical year

Safe to plant

May 9

frost is over in 9 of 10 years

First fall frost

October 9

typical year

Growing season

165 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 – Mar 30 – Apr 13 –
Spinach – Mar 16 – Apr 6 Aug 14 – 28
Lettuce – Mar 30 – Apr 20 Aug 14 – 28
Radishes – Mar 30 – May 11 Aug 28 – Sep 11
Onions – Mar 30 – Apr 13 –
Potatoes – Apr 6 – 20 –
Carrots – Apr 6 – 27 Jul 17 – 31
Beets – Mar 30 – Apr 13 Jul 31 – Aug 14
Kale Feb 16 – Mar 2 Mar 30 – Apr 13 Jul 31 – Aug 14
Broccoli Feb 16 – Mar 2 Apr 13 – 27 Jul 31 – Aug 14
Cabbage Feb 2 – 16 Mar 30 – Apr 13 Jul 31 – Aug 14
Garlic – – Aug 28 – Sep 18
Warm-season crops
Tomatoes Mar 14 – 28 May 9 – 23 –
Peppers Mar 7 – 21 May 16 – 30 –
Cucumbers – May 9 – 30 –
Zucchini – May 9 – Jun 6 –
Pumpkins – May 9 – 30 –
Green beans – May 9 – Jul 31 –
Sweet corn – May 9 – Jun 6 –
Basil Apr 4 – 18 May 16 – 23 –

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 9April 27April 13
Fall frost before September 28October 9October 20

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 14 (April 30 in a late year), and the first one in fall around October 18.

Where these dates come from

NOAA weather station DEWEY, UT US (USC00422150), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 30 miles:

84515, 84540

1 of these zip codes are more than 30 miles from the station, so their real frost dates may differ by a week or more.

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