Frost Report

All states Arizona

Frost dates for Sonoita, AZ

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

March 28

typical year

Safe to plant

April 21

frost is over in 9 of 10 years

First fall frost

November 21

typical year

Growing season

237 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 – Feb 28 – Mar 14 –
Spinach – Feb 14 – Mar 7 Sep 26 – Oct 10
Lettuce – Feb 28 – Mar 21 Sep 26 – Oct 10
Radishes – Feb 28 – Apr 11 Oct 10 – 24
Onions – Feb 28 – Mar 14 –
Potatoes – Mar 7 – 21 –
Carrots – Mar 7 – 28 Aug 29 – Sep 12
Beets – Feb 28 – Mar 14 Sep 12 – 26
Kale Jan 17 – 31 Feb 28 – Mar 14 Sep 12 – 26
Broccoli Jan 17 – 31 Mar 14 – 28 Sep 12 – 26
Cabbage Jan 3 – 17 Feb 28 – Mar 14 Sep 12 – 26
Garlic – – Oct 10 – 31
Warm-season crops
Tomatoes Feb 24 – Mar 10 Apr 21 – May 5 –
Peppers Feb 17 – Mar 3 Apr 28 – May 12 –
Cucumbers – Apr 21 – May 12 –
Zucchini – Apr 21 – May 19 –
Pumpkins – Apr 21 – May 12 –
Green beans – Apr 21 – Sep 12 –
Sweet corn – Apr 21 – May 19 –
Basil Mar 17 – 31 Apr 28 – May 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 April 21March 28March 1
Fall frost before November 5November 21December 7

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 March 1 (April 4 in a late year), and the first one in fall around December 2.

Where these dates come from

NOAA weather station SONOITA, AZ US (USC00027990), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 3 miles:

85637

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