Frost Report

All states Colorado

Frost dates for Cortez, CO

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 27

typical year

Safe to plant

June 11

frost is over in 9 of 10 years

First fall frost

September 28

typical year

Growing season

125 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 29 – May 13 –
Spinach – Apr 15 – May 6 Aug 3 – 17
Lettuce – Apr 29 – May 20 Aug 3 – 17
Radishes – Apr 29 – Jun 10 Aug 17 – 31
Onions – Apr 29 – May 13 –
Potatoes – May 6 – 20 –
Carrots – May 6 – 27 Jul 6 – 20
Beets – Apr 29 – May 13 Jul 20 – Aug 3
Kale Mar 18 – Apr 1 Apr 29 – May 13 Jul 20 – Aug 3
Broccoli Mar 18 – Apr 1 May 13 – 27 Jul 20 – Aug 3
Cabbage Mar 4 – 18 Apr 29 – May 13 Jul 20 – Aug 3
Garlic – – Aug 17 – Sep 7
Warm-season crops
Tomatoes Apr 16 – 30 Jun 11 – 25 –
Peppers Apr 9 – 23 Jun 18 – Jul 2 –
Cucumbers – Jun 11 – Jul 2 –
Zucchini – Jun 11 – Jul 9 –
Pumpkins – Jun 11 – Jul 2 –
Green beans – Jun 11 – Jul 20 –
Sweet corn – Jun 11 – Jul 9 –
Basil May 7 – 21 Jun 18 – 25 –

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 11May 27May 9
Fall frost before September 17September 28October 10

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 8 (May 31 in a late year), and the first one in fall around October 7.

Towns that use these dates

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

Cortez

Where these dates come from

NOAA weather station CORTEZ MONTEZUMA CO AP, CO US (USW00093069), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 6 miles:

81321

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