Last spring frost
May 20
Frost Dates for Grand Ronde, OR
First fall frost
Oct 23
Growing season
157 days
Hardiness zone
8b
In an average year around Grand Ronde, OR, the last spring frost (32°F) is about May 20 and the first fall frost is about Oct 23, giving roughly a 157-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 30 | Jun 10 | May 24 |
| Freeze (32°F) | Jun 8 | May 20 | Apr 28 |
| Hard (28°F) | May 20 | Apr 27 | Mar 31 |
| Severe (24°F) | Apr 27 | Mar 28 | Feb 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 23 | Jun 18 | Jun 14 | Jun 10 | Jun 7 | Jun 3 | May 31 | May 24 |
| 32°F | Jun 8 | Jun 2 | May 30 | May 26 | May 20 | May 15 | May 9 | May 3 | Apr 28 |
| 28°F | May 20 | May 10 | May 5 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 13 | Mar 31 |
| 24°F | Apr 27 | Apr 18 | Apr 9 | Apr 2 | Mar 28 | Mar 21 | Mar 9 | Feb 25 | Feb 8 |
| 20°F | Mar 29 | Mar 14 | Mar 2 | Feb 24 | Feb 14 | Feb 3 | Jan 19 | Jan 5 | Dec 20 |
| 16°F | Feb 24 | Feb 16 | Feb 7 | Jan 30 | Jan 12 | Jan 3 | Dec 28 | Dec 15 | Dec 6 |
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 9 | Oct 4 | Oct 21 |
| Freeze (32°F) | Oct 5 | Oct 23 | Nov 9 |
| Hard (28°F) | Oct 23 | Nov 10 | Dec 1 |
| Severe (24°F) | Nov 1 | Nov 28 | Dec 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 9 | Sep 22 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 15 | Oct 21 |
| 32°F | Oct 5 | Oct 13 | Oct 16 | Oct 20 | Oct 23 | Oct 26 | Oct 30 | Nov 4 | Nov 9 |
| 28°F | Oct 23 | Oct 29 | Nov 2 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 24 | Dec 1 |
| 24°F | Nov 1 | Nov 10 | Nov 16 | Nov 23 | Nov 28 | Dec 2 | Dec 7 | Dec 17 | Dec 31 |
| 20°F | Nov 11 | Nov 23 | Dec 1 | Dec 7 | Dec 17 | Dec 25 | Jan 1 | Jan 11 | Feb 6 |
| 16°F | Nov 24 | Dec 3 | Dec 9 | Dec 18 | Dec 27 | Jan 1 | Jan 8 | Jan 26 | Feb 10 |
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: Laurel Mtn, Or, about 11.5 miles away@if(!empty($station['elevation_ft'])), at 3,589 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 Grand Ronde, OR?
On average, the last spring frost (32°F) around Grand Ronde, OR is about May 20. 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 Grand Ronde, OR typically arrives about Oct 23. 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 20 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 157 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 97347 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026