Last spring frost
Mar 31
Frost Dates for Winston, OR
First fall frost
Nov 6
Growing season
221 days
Hardiness zone
9a
In an average year around Winston, OR, the last spring frost (32°F) is about Mar 31 and the first fall frost is about Nov 6, giving roughly a 221-day growing season. To be safe most years, wait until Feb 27 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) | May 14 | Apr 27 | Apr 8 |
| Freeze (32°F) | Apr 27 | Mar 31 | Feb 27 |
| Hard (28°F) | Mar 31 | Feb 20 | Dec 22 |
| Severe (24°F) | Feb 24 | Jan 6 | Nov 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 14 | May 9 | May 4 | Apr 30 | Apr 27 | Apr 23 | Apr 20 | Apr 14 | Apr 8 |
| 32°F | Apr 27 | Apr 18 | Apr 11 | Apr 5 | Mar 31 | Mar 26 | Mar 20 | Mar 10 | Feb 27 |
| 28°F | Mar 31 | Mar 18 | Mar 7 | Feb 28 | Feb 20 | Feb 14 | Feb 1 | Jan 14 | Dec 22 |
| 24°F | Feb 24 | Feb 15 | Feb 1 | Jan 17 | Jan 6 | Dec 30 | Dec 16 | Dec 7 | Nov 19 |
| 20°F | Jan 15 | Dec 31 | Dec 29 | Dec 23 | Dec 15 | Dec 12 | Dec 9 | Nov 30 | Nov 10 |
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 28 | Oct 14 | Nov 7 |
| Freeze (32°F) | Oct 11 | Nov 6 | Dec 13 |
| Hard (28°F) | Oct 28 | Dec 10 | Feb 12 |
| Severe (24°F) | Nov 3 | Dec 21 | Feb 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 28 | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 24 | Oct 30 | Nov 7 |
| 32°F | Oct 11 | Oct 20 | Oct 26 | Oct 31 | Nov 6 | Nov 15 | Nov 25 | Dec 4 | Dec 13 |
| 28°F | Oct 28 | Nov 7 | Nov 19 | Dec 2 | Dec 10 | Dec 22 | Jan 1 | Jan 15 | Feb 12 |
| 24°F | Nov 3 | Nov 19 | Dec 1 | Dec 10 | Dec 21 | Dec 29 | Jan 10 | Jan 30 | Feb 17 |
| 20°F | Nov 10 | Nov 30 | Dec 7 | Dec 10 | Dec 12 | Dec 20 | Dec 26 | Dec 31 | Jan 13 |
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: Riddle, Or, about 9.9 miles away@if(!empty($station['elevation_ft'])), at 680 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 Winston, OR?
On average, the last spring frost (32°F) around Winston, OR is about Mar 31. In cooler years it can run later, so for a safer bet many gardeners wait until Feb 27.
When is the first frost in the fall?
The first fall frost around Winston, OR typically arrives about Nov 6. 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 Mar 31 on average, or Feb 27 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 221 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 97496 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026