Last spring frost
May 31
Frost Dates for Bly, OR
First fall frost
Sep 21
Growing season
114 days
Hardiness zone
6b
In an average year around Bly, OR, the last spring frost (32°F) is about May 31 and the first fall frost is about Sep 21, giving roughly a 114-day growing season. To be safe most years, wait until May 7 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 30 | Jun 14 | May 29 |
| Freeze (32°F) | Jun 17 | May 31 | May 7 |
| Hard (28°F) | May 30 | May 5 | Apr 20 |
| Severe (24°F) | May 7 | Apr 17 | Mar 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 25 | Jun 21 | Jun 18 | Jun 14 | Jun 12 | Jun 8 | Jun 4 | May 29 |
| 32°F | Jun 17 | Jun 11 | Jun 6 | Jun 3 | May 31 | May 25 | May 20 | May 14 | May 7 |
| 28°F | May 30 | May 19 | May 14 | May 9 | May 5 | May 2 | Apr 30 | Apr 25 | Apr 20 |
| 24°F | May 7 | Apr 30 | Apr 25 | Apr 22 | Apr 17 | Apr 13 | Apr 9 | Apr 5 | Mar 31 |
| 20°F | Apr 17 | Apr 8 | Apr 4 | Mar 31 | Mar 25 | Mar 21 | Mar 16 | Mar 9 | Mar 1 |
| 16°F | Mar 28 | Mar 19 | Mar 12 | Mar 7 | Mar 3 | Feb 28 | Feb 22 | Feb 15 | Feb 4 |
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 25 | Sep 10 | Sep 21 |
| Freeze (32°F) | Sep 6 | Sep 21 | Oct 4 |
| Hard (28°F) | Sep 19 | Oct 4 | Oct 19 |
| Severe (24°F) | Oct 4 | Oct 20 | Nov 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 25 | Sep 1 | Sep 4 | Sep 8 | Sep 10 | Sep 13 | Sep 15 | Sep 18 | Sep 21 |
| 32°F | Sep 6 | Sep 11 | Sep 15 | Sep 18 | Sep 21 | Sep 23 | Sep 26 | Sep 29 | Oct 4 |
| 28°F | Sep 19 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 19 |
| 24°F | Oct 4 | Oct 8 | Oct 12 | Oct 16 | Oct 20 | Oct 24 | Oct 29 | Nov 2 | Nov 7 |
| 20°F | Oct 22 | Oct 28 | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 16 | Nov 21 | Nov 29 |
| 16°F | Nov 2 | Nov 8 | Nov 12 | Nov 17 | Nov 22 | Nov 26 | Dec 1 | Dec 5 | Dec 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: Gerber Dam, Or, about 14.3 miles away@if(!empty($station['elevation_ft'])), at 4,870 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 Bly, OR?
On average, the last spring frost (32°F) around Bly, OR is about May 31. In cooler years it can run later, so for a safer bet many gardeners wait until May 7.
When is the first frost in the fall?
The first fall frost around Bly, OR typically arrives about Sep 21. 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 31 on average, or May 7 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 114 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 97622 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026