Last spring frost
May 15
Frost Dates for Halfway, OR
First fall frost
Sep 24
Growing season
130 days
Hardiness zone
6b
In an average year around Halfway, OR, the last spring frost (32°F) is about May 15 and the first fall frost is about Sep 24, giving roughly a 130-day growing season. To be safe most years, wait until May 2 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 24 | Jun 5 | May 18 |
| Freeze (32°F) | Jun 2 | May 15 | May 2 |
| Hard (28°F) | May 16 | May 2 | Apr 18 |
| Severe (24°F) | May 3 | Apr 16 | Mar 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 24 | Jun 17 | Jun 13 | Jun 9 | Jun 5 | Jun 3 | May 31 | May 26 | May 18 |
| 32°F | Jun 2 | May 28 | May 22 | May 18 | May 15 | May 13 | May 10 | May 7 | May 2 |
| 28°F | May 16 | May 11 | May 8 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 23 | Apr 18 |
| 24°F | May 3 | Apr 28 | Apr 24 | Apr 20 | Apr 16 | Apr 8 | Apr 3 | Mar 30 | Mar 19 |
| 20°F | Apr 13 | Apr 3 | Mar 28 | Mar 20 | Mar 14 | Mar 11 | Mar 8 | Mar 5 | Feb 28 |
| 16°F | Mar 15 | Mar 10 | Mar 7 | Mar 4 | Mar 2 | Feb 27 | Feb 24 | Feb 20 | Feb 14 |
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 28 | Sep 12 | Sep 26 |
| Freeze (32°F) | Sep 9 | Sep 24 | Oct 6 |
| Hard (28°F) | Sep 22 | Oct 5 | Oct 21 |
| Severe (24°F) | Oct 1 | Oct 18 | Nov 3 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 28 | Sep 2 | Sep 6 | Sep 9 | Sep 12 | Sep 15 | Sep 18 | Sep 22 | Sep 26 |
| 32°F | Sep 9 | Sep 14 | Sep 18 | Sep 21 | Sep 24 | Sep 27 | Sep 30 | Oct 2 | Oct 6 |
| 28°F | Sep 22 | Sep 26 | Sep 30 | Oct 2 | Oct 5 | Oct 7 | Oct 11 | Oct 15 | Oct 21 |
| 24°F | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 25 | Oct 29 | Nov 3 |
| 20°F | Oct 13 | Oct 20 | Oct 24 | Oct 28 | Nov 1 | Nov 4 | Nov 9 | Nov 15 | Nov 22 |
| 16°F | Oct 26 | Nov 1 | Nov 5 | Nov 10 | Nov 15 | Nov 20 | Nov 24 | Nov 30 | Dec 6 |
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: Halfway, Or, about 12.1 miles away@if(!empty($station['elevation_ft'])), at 2,653 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 Halfway, OR?
On average, the last spring frost (32°F) around Halfway, OR is about May 15. In cooler years it can run later, so for a safer bet many gardeners wait until May 2.
When is the first frost in the fall?
The first fall frost around Halfway, OR typically arrives about Sep 24. 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 15 on average, or May 2 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 130 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 97834 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026