Frost Report

All states Washington

Frost dates for Mcnary Dam, WA

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 27

typical year

Safe to plant

April 14

frost is over in 9 of 10 years

First fall frost

November 4

typical year

Growing season

221 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 27 – Mar 13 –
Spinach – Feb 13 – Mar 6 Sep 9 – 23
Lettuce – Feb 27 – Mar 20 Sep 9 – 23
Radishes – Feb 27 – Apr 10 Sep 23 – Oct 7
Onions – Feb 27 – Mar 13 –
Potatoes – Mar 6 – 20 –
Carrots – Mar 6 – 27 Aug 12 – 26
Beets – Feb 27 – Mar 13 Aug 26 – Sep 9
Kale Jan 16 – 30 Feb 27 – Mar 13 Aug 26 – Sep 9
Broccoli Jan 16 – 30 Mar 13 – 27 Aug 26 – Sep 9
Cabbage Jan 2 – 16 Feb 27 – Mar 13 Aug 26 – Sep 9
Garlic – – Sep 23 – Oct 14
Warm-season crops
Tomatoes Feb 17 – Mar 3 Apr 14 – 28 –
Peppers Feb 10 – 24 Apr 21 – May 5 –
Cucumbers – Apr 14 – May 5 –
Zucchini – Apr 14 – May 12 –
Pumpkins – Apr 14 – May 5 –
Green beans – Apr 14 – Aug 26 –
Sweet corn – Apr 14 – May 12 –
Basil Mar 10 – 24 Apr 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 April 14March 27March 8
Fall frost before October 21November 4November 22

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 6 (March 28 in a late year), and the first one in fall around November 18.

Where these dates come from

NOAA weather station MCNARY DAM, WA US (USC00455231), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 6 miles:

99346

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