Frost dates for Mount Vernon, 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 24
typical year
Safe to plant
April 14
frost is over in 9 of 10 years
First fall frost
November 3
typical year
Growing season
224 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Feb 24 – Mar 10 | – |
| Spinach | – | Feb 10 – Mar 3 | Sep 8 – 22 |
| Lettuce | – | Feb 24 – Mar 17 | Sep 8 – 22 |
| Radishes | – | Feb 24 – Apr 7 | Sep 22 – Oct 6 |
| Onions | – | Feb 24 – Mar 10 | – |
| Potatoes | – | Mar 3 – 17 | – |
| Carrots | – | Mar 3 – 24 | Aug 11 – 25 |
| Beets | – | Feb 24 – Mar 10 | Aug 25 – Sep 8 |
| Kale | Jan 13 – 27 | Feb 24 – Mar 10 | Aug 25 – Sep 8 |
| Broccoli | Jan 13 – 27 | Mar 10 – 24 | Aug 25 – Sep 8 |
| Cabbage | Dec 30 – Jan 13 | Feb 24 – Mar 10 | Aug 25 – Sep 8 |
| Garlic | – | – | Sep 22 – Oct 13 |
| 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 25 | – |
| 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 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | April 14 | March 24 | March 3 |
| Fall frost before | October 12 | November 3 | November 25 |
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 27 (March 17 in a late year), and the first one in fall around November 25.
Towns that use these dates
This is the nearest NOAA station with frost records for 3 towns.
Mount Vernon, Burlington, La Conner
Where these dates come from
NOAA weather station MT VERNON 3 WNW, WA US (USC00455678), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 9 miles:
98232, 98233, 98238, 98257, 98273
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.