Last spring frost
Apr 2
Frost Dates for Halfway, OR
First fall frost
Nov 5
Growing season
216 days
Hardiness zone
7a
In an average year around Halfway, OR, the last spring frost (32°F) is about Apr 2 and the first fall frost is about Nov 5, giving roughly a 216-day growing season. To be safe most years, wait until Mar 15 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 7 | Apr 21 | Apr 6 |
| Freeze (32°F) | Apr 20 | Apr 2 | Mar 15 |
| Hard (28°F) | Apr 1 | Mar 13 | Feb 26 |
| Severe (24°F) | Mar 15 | Feb 28 | Feb 5 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 7 | May 2 | Apr 28 | Apr 25 | Apr 21 | Apr 18 | Apr 14 | Apr 10 | Apr 6 |
| 32°F | Apr 20 | Apr 13 | Apr 9 | Apr 5 | Apr 2 | Mar 30 | Mar 27 | Mar 20 | Mar 15 |
| 28°F | Apr 1 | Mar 26 | Mar 21 | Mar 16 | Mar 13 | Mar 10 | Mar 6 | Mar 2 | Feb 26 |
| 24°F | Mar 15 | Mar 10 | Mar 6 | Mar 2 | Feb 28 | Feb 25 | Feb 19 | Feb 14 | Feb 5 |
| 20°F | Mar 4 | Feb 28 | Feb 23 | Feb 18 | Feb 14 | Feb 8 | Feb 2 | Jan 26 | Jan 12 |
| 16°F | Feb 23 | Feb 17 | Feb 10 | Feb 3 | Jan 28 | Jan 20 | Jan 10 | Jan 2 | Dec 23 |
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) | Oct 13 | Oct 26 | Nov 8 |
| Freeze (32°F) | Oct 24 | Nov 5 | Nov 19 |
| Hard (28°F) | Nov 1 | Nov 16 | Nov 30 |
| Severe (24°F) | Nov 6 | Nov 26 | Dec 16 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 13 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 28 | Oct 30 | Nov 3 | Nov 8 |
| 32°F | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 19 |
| 28°F | Nov 1 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 26 | Nov 30 |
| 24°F | Nov 6 | Nov 13 | Nov 19 | Nov 23 | Nov 26 | Nov 29 | Dec 4 | Dec 9 | Dec 16 |
| 20°F | Nov 13 | Nov 23 | Nov 28 | Dec 1 | Dec 7 | Dec 11 | Dec 17 | Dec 24 | Jan 3 |
| 16°F | Nov 23 | Nov 30 | Dec 6 | Dec 11 | Dec 18 | Dec 26 | Jan 1 | Jan 8 | Jan 22 |
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: Brownlee Dam, Id, about 2.5 miles away@if(!empty($station['elevation_ft'])), at 1,844 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 Apr 2. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 15.
When is the first frost in the fall?
The first fall frost around Halfway, OR typically arrives about Nov 5. 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 Apr 2 on average, or Mar 15 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 216 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 97840 Planting calendar → Oregon frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026