Frost dates for Mattawa, 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 7
frost is over in 9 of 10 years
First fall frost
November 4
typical year
Growing season
222 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 9 – 23 |
| Lettuce | – | Feb 24 – Mar 17 | Sep 9 – 23 |
| Radishes | – | Feb 24 – Apr 7 | Sep 23 – Oct 7 |
| Onions | – | Feb 24 – Mar 10 | – |
| Potatoes | – | Mar 3 – 17 | – |
| Carrots | – | Mar 3 – 24 | Aug 12 – 26 |
| Beets | – | Feb 24 – Mar 10 | Aug 26 – Sep 9 |
| Kale | Jan 13 – 27 | Feb 24 – Mar 10 | Aug 26 – Sep 9 |
| Broccoli | Jan 13 – 27 | Mar 10 – 24 | Aug 26 – Sep 9 |
| Cabbage | Dec 30 – Jan 13 | Feb 24 – Mar 10 | Aug 26 – Sep 9 |
| Garlic | – | – | Sep 23 – Oct 14 |
| Warm-season crops | |||
| Tomatoes | Feb 10 – 24 | Apr 7 – 21 | – |
| Peppers | Feb 3 – 17 | Apr 14 – 28 | – |
| Cucumbers | – | Apr 7 – 28 | – |
| Zucchini | – | Apr 7 – May 5 | – |
| Pumpkins | – | Apr 7 – 28 | – |
| Green beans | – | Apr 7 – Aug 26 | – |
| Sweet corn | – | Apr 7 – May 5 | – |
| Basil | Mar 3 – 17 | Apr 14 – 21 | – |
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 7 | March 24 | March 4 |
| Fall frost before | October 23 | November 4 | November 18 |
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 5 (March 25 in a late year), and the first one in fall around November 16.
Towns that use these dates
This is the nearest NOAA station with frost records for 1 town.
Mattawa
Where these dates come from
NOAA weather station PRIEST RAPIDS DAM, WA US (USC00456747), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 15 miles:
98944, 98950
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.