Last spring frost
Apr 29
Frost Dates for Cascadia, OR
First fall frost
Oct 13
Growing season
167 days
Hardiness zone
8b
In an average year around Cascadia, OR, the last spring frost (32°F) is about Apr 29 and the first fall frost is about Oct 13, giving roughly a 167-day growing season. To be safe most years, wait until Apr 5 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 12 | May 21 | May 2 |
| Freeze (32°F) | May 17 | Apr 29 | Apr 5 |
| Hard (28°F) | Apr 28 | Mar 30 | Feb 26 |
| Severe (24°F) | Mar 23 | Feb 19 | Dec 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 12 | Jun 5 | May 31 | May 26 | May 21 | May 16 | May 12 | May 7 | May 2 |
| 32°F | May 17 | May 10 | May 6 | May 2 | Apr 29 | Apr 25 | Apr 19 | Apr 14 | Apr 5 |
| 28°F | Apr 28 | Apr 16 | Apr 9 | Apr 2 | Mar 30 | Mar 25 | Mar 15 | Mar 7 | Feb 26 |
| 24°F | Mar 23 | Mar 9 | Mar 1 | Feb 25 | Feb 19 | Feb 12 | Feb 2 | Jan 19 | Dec 31 |
| 20°F | Feb 23 | Feb 14 | Feb 2 | Jan 23 | Jan 10 | Jan 2 | Dec 26 | Dec 15 | Dec 4 |
| 16°F | Feb 7 | Jan 23 | Jan 7 | Dec 31 | Dec 28 | Dec 23 | Dec 16 | Dec 11 | Dec 5 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Aug 30 | Sep 21 | Oct 14 |
| Freeze (32°F) | Sep 22 | Oct 13 | Nov 6 |
| Hard (28°F) | Oct 12 | Nov 5 | Dec 4 |
| Severe (24°F) | Oct 31 | Dec 1 | Jan 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 30 | Sep 5 | Sep 9 | Sep 15 | Sep 21 | Sep 28 | Oct 3 | Oct 7 | Oct 14 |
| 32°F | Sep 22 | Sep 29 | Oct 3 | Oct 8 | Oct 13 | Oct 17 | Oct 22 | Oct 28 | Nov 6 |
| 28°F | Oct 12 | Oct 21 | Oct 27 | Nov 1 | Nov 5 | Nov 10 | Nov 17 | Nov 24 | Dec 4 |
| 24°F | Oct 31 | Nov 10 | Nov 17 | Nov 23 | Dec 1 | Dec 6 | Dec 14 | Dec 24 | Jan 6 |
| 20°F | Nov 13 | Nov 25 | Dec 3 | Dec 11 | Dec 20 | Dec 27 | Jan 1 | Jan 14 | Feb 9 |
| 16°F | Nov 30 | Dec 7 | Dec 12 | Dec 17 | Dec 23 | Dec 28 | Jan 1 | Jan 11 | Feb 1 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Cascadia, Or, about 9.6 miles away@if(!empty($station['elevation_ft'])), at 960 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Cascadia, OR?
On average, the last spring frost (32°F) around Cascadia, OR is about Apr 29. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 5.
When is the first frost in the fall?
The first fall frost around Cascadia, OR typically arrives about Oct 13. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 29 on average, or Apr 5 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 167 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 97329 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026