Frost Report

All states Oregon

Frost dates for Bonneville Dam, OR

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 14

typical year

Safe to plant

April 4

frost is over in 9 of 10 years

First fall frost

November 27

typical year

Growing season

257 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 14 – 28 –
Spinach – Jan 31 – Feb 21 Oct 2 – 16
Lettuce – Feb 14 – Mar 7 Oct 2 – 16
Radishes – Feb 14 – Mar 28 Oct 16 – 30
Onions – Feb 14 – 28 –
Potatoes – Feb 21 – Mar 7 –
Carrots – Feb 21 – Mar 14 Sep 4 – 18
Beets – Feb 14 – 28 Sep 18 – Oct 2
Kale Jan 3 – 17 Feb 14 – 28 Sep 18 – Oct 2
Broccoli Jan 3 – 17 Feb 28 – Mar 14 Sep 18 – Oct 2
Cabbage Dec 20 – Jan 3 Feb 14 – 28 Sep 18 – Oct 2
Garlic – – Oct 16 – Nov 6
Warm-season crops
Tomatoes Feb 7 – 21 Apr 4 – 18 –
Peppers Jan 31 – Feb 14 Apr 11 – 25 –
Cucumbers – Apr 4 – 25 –
Zucchini – Apr 4 – May 2 –
Pumpkins – Apr 4 – 25 –
Green beans – Apr 4 – Sep 18 –
Sweet corn – Apr 4 – May 2 –
Basil Feb 28 – Mar 14 Apr 11 – 18 –

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 4March 14February 19
Fall frost before November 8November 27December 15

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 February 14 (March 10 in a late year), and the first one in fall around December 14.

Towns that use these dates

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

North Bonneville, WA

Where these dates come from

NOAA weather station BONNEVILLE DAM, OR US (USC00350897), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 1 miles:

98639

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