Frost dates for Sammamish, 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 30
typical year
Safe to plant
April 21
frost is over in 9 of 10 years
First fall frost
November 7
typical year
Growing season
223 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 | – | Mar 2 – 16 | – |
| Spinach | – | Feb 16 – Mar 9 | Sep 12 – 26 |
| Lettuce | – | Mar 2 – 23 | Sep 12 – 26 |
| Radishes | – | Mar 2 – Apr 13 | Sep 26 – Oct 10 |
| Onions | – | Mar 2 – 16 | – |
| Potatoes | – | Mar 9 – 23 | – |
| Carrots | – | Mar 9 – 30 | Aug 15 – 29 |
| Beets | – | Mar 2 – 16 | Aug 29 – Sep 12 |
| Kale | Jan 19 – Feb 2 | Mar 2 – 16 | Aug 29 – Sep 12 |
| Broccoli | Jan 19 – Feb 2 | Mar 16 – 30 | Aug 29 – Sep 12 |
| Cabbage | Jan 5 – 19 | Mar 2 – 16 | Aug 29 – Sep 12 |
| Garlic | – | – | Sep 26 – Oct 17 |
| Warm-season crops | |||
| Tomatoes | Feb 24 – Mar 10 | Apr 21 – May 5 | – |
| Peppers | Feb 17 – Mar 3 | Apr 28 – May 12 | – |
| Cucumbers | – | Apr 21 – May 12 | – |
| Zucchini | – | Apr 21 – May 19 | – |
| Pumpkins | – | Apr 21 – May 12 | – |
| Green beans | – | Apr 21 – Aug 29 | – |
| Sweet corn | – | Apr 21 – May 19 | – |
| Basil | Mar 17 – 31 | Apr 28 – May 5 | – |
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 21 | March 30 | March 4 |
| Fall frost before | October 22 | November 7 | December 1 |
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 25 in a late year), and the first one in fall around November 29.
Towns that use these dates
This is the nearest NOAA station with frost records for 4 towns.
Sammamish, Snoqualmie, North Bend, Carnation
Where these dates come from
NOAA weather station SNOQUALMIE FALLS, WA US (USC00457773), 1991–2020 climate normals. It's the nearest station for 6 zip codes, all within 10 miles:
98024, 98027, 98029, 98050, 98065, 98075
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.