Last spring frost
Jun 5
Frost Dates for Keno, OR
First fall frost
Sep 20
Growing season
107 days
Hardiness zone
6b
In an average year around Keno, OR, the last spring frost (32°F) is about Jun 5 and the first fall frost is about Sep 20, giving roughly a 107-day growing season. To be safe most years, wait until May 16 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) | Jul 8 | Jun 21 | Jun 5 |
| Freeze (32°F) | Jun 22 | Jun 5 | May 16 |
| Hard (28°F) | Jun 7 | May 14 | Apr 29 |
| Severe (24°F) | May 14 | Apr 26 | Apr 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jul 8 | Jul 1 | Jun 26 | Jun 23 | Jun 21 | Jun 18 | Jun 15 | Jun 10 | Jun 5 |
| 32°F | Jun 22 | Jun 17 | Jun 13 | Jun 9 | Jun 5 | Jun 2 | May 30 | May 24 | May 16 |
| 28°F | Jun 7 | May 30 | May 23 | May 17 | May 14 | May 10 | May 6 | May 3 | Apr 29 |
| 24°F | May 14 | May 5 | May 1 | Apr 28 | Apr 26 | Apr 23 | Apr 19 | Apr 15 | Apr 9 |
| 20°F | Apr 23 | Apr 16 | Apr 11 | Apr 8 | Apr 5 | Mar 31 | Mar 27 | Mar 20 | Mar 12 |
| 16°F | Apr 4 | Mar 27 | Mar 21 | Mar 14 | Mar 10 | Mar 4 | Feb 28 | Feb 19 | Feb 11 |
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 24 | Sep 8 | Sep 19 |
| Freeze (32°F) | Sep 6 | Sep 20 | Oct 4 |
| Hard (28°F) | Sep 19 | Oct 4 | Oct 20 |
| Severe (24°F) | Oct 3 | Oct 19 | Nov 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 24 | Aug 30 | Sep 2 | Sep 5 | Sep 8 | Sep 10 | Sep 13 | Sep 16 | Sep 19 |
| 32°F | Sep 6 | Sep 11 | Sep 14 | Sep 17 | Sep 20 | Sep 23 | Sep 25 | Sep 29 | Oct 4 |
| 28°F | Sep 19 | Sep 24 | Sep 28 | Oct 1 | Oct 4 | Oct 6 | Oct 10 | Oct 14 | Oct 20 |
| 24°F | Oct 3 | Oct 8 | Oct 12 | Oct 15 | Oct 19 | Oct 23 | Oct 27 | Nov 1 | Nov 8 |
| 20°F | Oct 17 | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 8 | Nov 13 | Nov 19 | Nov 25 |
| 16°F | Nov 1 | Nov 7 | Nov 12 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 4 | Dec 12 |
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: Keno, Or, about 8.9 miles away@if(!empty($station['elevation_ft'])), at 4,128 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 Keno, OR?
On average, the last spring frost (32°F) around Keno, OR is about Jun 5. In cooler years it can run later, so for a safer bet many gardeners wait until May 16.
When is the first frost in the fall?
The first fall frost around Keno, OR typically arrives about Sep 20. 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 Jun 5 on average, or May 16 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 107 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 97627 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026