Last spring frost
May 15
Frost Dates for Summit, OR
First fall frost
Oct 8
Growing season
145 days
Hardiness zone
8b
In an average year around Summit, OR, the last spring frost (32°F) is about May 15 and the first fall frost is about Oct 8, giving roughly a 145-day growing season. To be safe most years, wait until Apr 28 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 26 | Jun 8 | May 21 |
| Freeze (32°F) | Jun 2 | May 15 | Apr 28 |
| Hard (28°F) | May 10 | Apr 25 | Apr 2 |
| Severe (24°F) | Apr 20 | Mar 22 | Feb 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 26 | Jun 21 | Jun 17 | Jun 12 | Jun 8 | Jun 4 | May 31 | May 28 | May 21 |
| 32°F | Jun 2 | May 29 | May 23 | May 19 | May 15 | May 12 | May 7 | May 2 | Apr 28 |
| 28°F | May 10 | May 5 | May 1 | Apr 29 | Apr 25 | Apr 21 | Apr 17 | Apr 12 | Apr 2 |
| 24°F | Apr 20 | Apr 10 | Apr 3 | Mar 28 | Mar 22 | Mar 13 | Mar 5 | Feb 28 | Feb 19 |
| 20°F | Mar 4 | Feb 26 | Feb 19 | Feb 13 | Feb 3 | Jan 28 | Jan 14 | Jan 4 | Dec 18 |
| 16°F | Feb 16 | Feb 1 | Jan 23 | Jan 11 | Jan 4 | Dec 31 | Dec 21 | Dec 11 | Nov 30 |
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) | Sep 3 | Sep 19 | Oct 5 |
| Freeze (32°F) | Sep 24 | Oct 8 | Oct 26 |
| Hard (28°F) | Oct 9 | Oct 28 | Nov 13 |
| Severe (24°F) | Oct 29 | Nov 14 | Dec 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 3 | Sep 6 | Sep 10 | Sep 15 | Sep 19 | Sep 23 | Sep 26 | Oct 1 | Oct 5 |
| 32°F | Sep 24 | Sep 29 | Oct 1 | Oct 5 | Oct 8 | Oct 12 | Oct 15 | Oct 19 | Oct 26 |
| 28°F | Oct 9 | Oct 17 | Oct 21 | Oct 25 | Oct 28 | Oct 30 | Nov 2 | Nov 7 | Nov 13 |
| 24°F | Oct 29 | Nov 2 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 23 | Nov 28 | Dec 7 |
| 20°F | Nov 8 | Nov 15 | Nov 21 | Nov 27 | Dec 1 | Dec 8 | Dec 16 | Dec 25 | Jan 7 |
| 16°F | Nov 18 | Nov 27 | Dec 3 | Dec 11 | Dec 19 | Dec 26 | Jan 1 | Jan 8 | Jan 26 |
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: Corvallis Water Bureau, Or, about 13.6 miles away@if(!empty($station['elevation_ft'])), at 592 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 Summit, OR?
On average, the last spring frost (32°F) around Summit, OR is about May 15. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 28.
When is the first frost in the fall?
The first fall frost around Summit, OR typically arrives about Oct 8. 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 May 15 on average, or Apr 28 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 145 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 97326 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026