Last spring frost
May 6
Frost Dates for La Grande, OR
First fall frost
Oct 1
Growing season
146 days
Hardiness zone
6b
In an average year around La Grande, OR, the last spring frost (32°F) is about May 6 and the first fall frost is about Oct 1, giving roughly a 146-day growing season. To be safe most years, wait until Apr 21 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 14 | May 26 | May 7 |
| Freeze (32°F) | May 26 | May 6 | Apr 21 |
| Hard (28°F) | May 5 | Apr 19 | Apr 1 |
| Severe (24°F) | Apr 19 | Mar 30 | Mar 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 14 | Jun 8 | Jun 3 | May 31 | May 26 | May 22 | May 18 | May 14 | May 7 |
| 32°F | May 26 | May 17 | May 13 | May 9 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 21 |
| 28°F | May 5 | Apr 30 | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 7 | Apr 1 |
| 24°F | Apr 19 | Apr 11 | Apr 6 | Apr 2 | Mar 30 | Mar 25 | Mar 20 | Mar 12 | Mar 6 |
| 20°F | Mar 29 | Mar 21 | Mar 13 | Mar 9 | Mar 6 | Mar 2 | Feb 27 | Feb 21 | Feb 15 |
| 16°F | Mar 8 | Mar 3 | Feb 27 | Feb 22 | Feb 17 | Feb 14 | Feb 8 | Feb 3 | Jan 20 |
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 3 |
| Freeze (32°F) | Sep 17 | Oct 1 | Oct 16 |
| Hard (28°F) | Sep 30 | Oct 14 | Oct 29 |
| Severe (24°F) | Oct 12 | Oct 29 | Nov 21 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 3 | Sep 8 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 25 | Sep 29 | Oct 3 |
| 32°F | Sep 17 | Sep 22 | Sep 27 | Sep 30 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 16 |
| 28°F | Sep 30 | Oct 3 | Oct 7 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
| 24°F | Oct 12 | Oct 19 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 5 | Nov 12 | Nov 21 |
| 20°F | Oct 24 | Oct 29 | Nov 3 | Nov 10 | Nov 15 | Nov 20 | Nov 23 | Nov 28 | Dec 4 |
| 16°F | Nov 1 | Nov 11 | Nov 19 | Nov 24 | Nov 28 | Dec 2 | Dec 6 | Dec 12 | Dec 21 |
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: La Grande, Or, about 4 miles away@if(!empty($station['elevation_ft'])), at 2,755 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 La Grande, OR?
On average, the last spring frost (32°F) around La Grande, OR is about May 6. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 21.
When is the first frost in the fall?
The first fall frost around La Grande, OR typically arrives about Oct 1. 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 6 on average, or Apr 21 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 146 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 97850 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026