Frost Report

All states Colorado

Frost dates for Basalt, 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 31

typical year

Safe to plant

June 14

frost is over in 9 of 10 years

First fall frost

September 23

typical year

Growing season

114 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 3 – 17 –
Spinach – Apr 19 – May 10 Jul 29 – Aug 12
Lettuce – May 3 – 24 Jul 29 – Aug 12
Radishes – May 3 – Jun 14 Aug 12 – 26
Onions – May 3 – 17 –
Potatoes – May 10 – 24 –
Carrots – May 10 – 31 Jul 1 – 15
Beets – May 3 – 17 Jul 15 – 29
Kale Mar 22 – Apr 5 May 3 – 17 Jul 15 – 29
Broccoli Mar 22 – Apr 5 May 17 – 31 Jul 15 – 29
Cabbage Mar 8 – 22 May 3 – 17 Jul 15 – 29
Garlic – – Aug 12 – Sep 2
Warm-season crops
Tomatoes Apr 19 – May 3 Jun 14 – 28 –
Peppers Apr 12 – 26 Jun 21 – Jul 5 –
Cucumbers – Jun 14 – Jul 5 –
Zucchini – Jun 14 – Jul 12 –
Pumpkins – Jun 14 – Jul 5 –
Green beans – Jun 14 – Jul 15 –
Sweet corn – Jun 14 – Jul 12 –
Basil May 10 – 24 Jun 21 – 28 –

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 14May 31May 16
Fall frost before September 11September 23October 3

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 13 (June 1 in a late year), and the first one in fall around October 2.

Towns that use these dates

This is the nearest NOAA station with frost records for 3 towns.

Basalt, Snowmass Village, Marble

Where these dates come from

NOAA weather station ASPEN PITKIN CO AP, CO US (USW00093073), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 16 miles:

81615, 81621, 81623, 81654, 81656

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