Frost dates for Lake Oswego, 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 18
typical year
Safe to plant
April 11
frost is over in 9 of 10 years
First fall frost
November 18
typical year
Growing season
244 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 18 – Mar 4 | – |
| Spinach | – | Feb 4 – 25 | Sep 23 – Oct 7 |
| Lettuce | – | Feb 18 – Mar 11 | Sep 23 – Oct 7 |
| Radishes | – | Feb 18 – Apr 1 | Oct 7 – 21 |
| Onions | – | Feb 18 – Mar 4 | – |
| Potatoes | – | Feb 25 – Mar 11 | – |
| Carrots | – | Feb 25 – Mar 18 | Aug 26 – Sep 9 |
| Beets | – | Feb 18 – Mar 4 | Sep 9 – 23 |
| Kale | Jan 7 – 21 | Feb 18 – Mar 4 | Sep 9 – 23 |
| Broccoli | Jan 7 – 21 | Mar 4 – 18 | Sep 9 – 23 |
| Cabbage | Dec 24 – Jan 7 | Feb 18 – Mar 4 | Sep 9 – 23 |
| Garlic | – | – | Oct 7 – 28 |
| Warm-season crops | |||
| Tomatoes | Feb 14 – 28 | Apr 11 – 25 | – |
| Peppers | Feb 7 – 21 | Apr 18 – May 2 | – |
| Cucumbers | – | Apr 11 – May 2 | – |
| Zucchini | – | Apr 11 – May 9 | – |
| Pumpkins | – | Apr 11 – May 2 | – |
| Green beans | – | Apr 11 – Sep 9 | – |
| Sweet corn | – | Apr 11 – May 9 | – |
| Basil | Mar 7 – 21 | Apr 18 – 25 | – |
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 11 | March 18 | February 19 |
| Fall frost before | October 30 | November 18 | December 12 |
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 12 (March 7 in a late year), and the first one in fall around December 8.
Towns that use these dates
This is the nearest NOAA station with frost records for 6 towns.
Lake Oswego, Oregon City, Happy Valley, West Linn, Gladstone, Johnson City
Where these dates come from
NOAA weather station OREGON CITY, OR US (USC00356334), 1991–2020 climate normals. It's the nearest station for 8 zip codes, all within 7 miles:
97015, 97027, 97034, 97045, 97068, 97086, 97222, 97267
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.