Frost dates for 97035 — Lake Oswego, OR
Last spring frostApr 1median date
First fall frostNov 6median date
Growing season219 daysfrost-free
Hardiness zone9aZone 9a
How Lake Oswego compares
- In 8 years out of 10, the last spring frost in Lake Oswego falls between March 5 and April 26, a 52-day window. The first fall frost falls between October 19 and December 1.
- The median last frost is 15 days earlier than the Oregon median of Apr 16.
- Its 219-day growing season is longer than 66% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 29 days later than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 42 nights a year at or below 32°F.
- Compared with Beaverton, OR, 10 km away, the last frost here is 49 days later than there and the growing season is 78 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 5 |
| 50% (median) | April 1 |
| 10% (safe for tender plants) | April 26 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 19 |
| 50% (median) | November 6 |
| 90% (late) | December 1 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Lake Oswego, OR
Frost dates for 97035 — Lake Oswego, OR — last frost Apr 1, first frost Nov 6, zone 9a. whenisthelastfrost.com
Crop
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Start indoors: Jan 7 to Jan 21Transplant outside: Mar 4 to Mar 18
Start indoors: Jan 21 to Feb 4Transplant outside: Apr 15 to Apr 29
Start indoors: Jan 21 to Feb 4Transplant outside: Apr 15 to Apr 29
Start indoors: Feb 4 to Feb 18Transplant outside: Apr 8 to Apr 22
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 11 to Mar 25Sow outdoors: Mar 4 to Apr 8Plant for fall: Sep 11 to Oct 9
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 4 to Mar 18Sow outdoors: Mar 4 to Mar 18Plant for fall: Aug 28 to Sep 18
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 18 to Apr 1Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 11 to Mar 25Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 18 to Apr 1Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 22 to May 6Sow outdoors: Apr 22 to May 6
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 8 to Apr 22
Sow outdoors: Feb 18 to Mar 11Plant for fall: Aug 14 to Sep 4
Sow outdoors: Feb 18 to Mar 11Plant for fall: Sep 11 to Oct 2
Sow outdoors: Feb 25 to Apr 8Plant for fall: Sep 25 to Oct 16
Start indoors: Mar 4 to Mar 11Transplant outside: Apr 15 to Apr 22Sow outdoors: Apr 8 to Apr 22Plant for fall: Aug 21 to Sep 4
Start indoors: Mar 4 to Mar 11Sow outdoors: Apr 8 to Apr 22Plant for fall: Aug 28 to Sep 11
Start indoors: Mar 4 to Mar 11Sow outdoors: Apr 8 to Apr 22
Start indoors: Mar 4 to Mar 11Transplant outside: Apr 15 to Apr 29
Sow outdoors: Mar 11 to Apr 8Plant for fall: Aug 14 to Aug 28
Sow outdoors: Mar 11 to Apr 8Plant for fall: Aug 28 to Sep 11
Sow outdoors: Mar 11 to Apr 1
Sow outdoors: Mar 18 to Apr 15Plant for fall: Aug 28 to Sep 11
Sow outdoors: Mar 18 to Apr 8Plant for fall: Sep 11 to Oct 2
Sow outdoors: Apr 8 to Apr 29Plant for fall: Aug 21 to Sep 4
Sow outdoors: Apr 8 to Apr 22
Transplant outside: Apr 15 to May 6
Plant for fall: Oct 23 to Nov 27
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Lake Oswego, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 7 – Jan 21 | Mar 4 – Mar 18 | — | — |
| Peppers | Jan 21 – Feb 4 | Apr 15 – Apr 29 | — | — |
| Eggplant | Jan 21 – Feb 4 | Apr 15 – Apr 29 | — | — |
| Tomatoes | Feb 4 – Feb 18 | Apr 8 – Apr 22 | — | — |
| Lettuce | Feb 4 – Feb 18 | Mar 11 – Mar 25 | Mar 4 – Apr 8 | Sep 11 – Oct 9 |
| Kale | Feb 4 – Feb 18 | Mar 4 – Mar 18 | Mar 4 – Mar 18 | Aug 28 – Sep 18 |
| Broccoli | Feb 4 – Feb 18 | Mar 18 – Apr 1 | — | Jul 31 – Aug 21 |
| Cabbage | Feb 4 – Feb 18 | Mar 11 – Mar 25 | — | Jul 31 – Aug 21 |
| Cauliflower | Feb 4 – Feb 18 | Mar 18 – Apr 1 | — | Jul 31 – Aug 21 |
| Okra | Feb 18 – Mar 4 | Apr 22 – May 6 | Apr 22 – May 6 | — |
| Basil | Feb 18 – Mar 4 | Apr 8 – Apr 22 | — | — |
| Peas | — | — | Feb 18 – Mar 11 | Aug 14 – Sep 4 |
| Spinach | — | — | Feb 18 – Mar 11 | Sep 11 – Oct 2 |
| Radishes | — | — | Feb 25 – Apr 8 | Sep 25 – Oct 16 |
| Cucumbers | Mar 4 – Mar 11 | Apr 15 – Apr 22 | Apr 8 – Apr 22 | Aug 21 – Sep 4 |
| Zucchini & Summer Squash | Mar 4 – Mar 11 | — | Apr 8 – Apr 22 | Aug 28 – Sep 11 |
| Winter Squash & Pumpkins | Mar 4 – Mar 11 | — | Apr 8 – Apr 22 | — |
| Melons & Watermelon | Mar 4 – Mar 11 | Apr 15 – Apr 29 | — | — |
| Carrots | — | — | Mar 11 – Apr 8 | Aug 14 – Aug 28 |
| Beets | — | — | Mar 11 – Apr 8 | Aug 28 – Sep 11 |
| Potatoes | — | — | Mar 11 – Apr 1 | — |
| Swiss Chard | — | — | Mar 18 – Apr 15 | Aug 28 – Sep 11 |
| Cilantro | — | — | Mar 18 – Apr 8 | Sep 11 – Oct 2 |
| Green Beans | — | — | Apr 8 – Apr 29 | Aug 21 – Sep 4 |
| Sweet Corn | — | — | Apr 8 – Apr 22 | — |
| Sweet Potatoes | — | Apr 15 – May 6 | — | — |
| Garlic | — | — | — | Oct 23 – Nov 27 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Beaverton 2 Ssw, OR weather station, 9 km away (elevation 269 ft (82 m)).
ZIP codes in Lake Oswego: 97034 97035
Frost dates near Lake Oswego
- Tualatin Apr 1 · Nov 6
- Marylhurst Mar 18 · Nov 18
- West Linn Mar 18 · Nov 18
- Beaverton Feb 11 · Dec 5
- Gladstone Mar 18 · Nov 18
- Portland Feb 25 · Dec 1
- Sherwood Mar 21 · Nov 22
- Wilsonville Mar 18 · Nov 13
Frequently asked questions
When is the last frost in Lake Oswego, OR?
The median last spring frost in Lake Oswego, OR is April 1. There is still about a 10% chance of frost after April 26, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Lake Oswego, OR?
The median first fall frost is November 6, with about a 10% chance of frost before October 19.
How long is the growing season in Lake Oswego, OR?
About 219 days between the median last spring frost and first fall frost.
What planting zone is Lake Oswego, OR?
Lake Oswego, OR is in USDA hardiness zone 9a.