Last spring frost
May 31
Frost Dates for Jordan Valley, ID
First fall frost
Oct 6
Growing season
128 days
Hardiness zone
7a
In an average year around Jordan Valley, ID, the last spring frost (32°F) is about May 31 and the first fall frost is about Oct 6, giving roughly a 128-day growing season. To be safe most years, wait until May 4 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 28 | Jun 12 | May 22 |
| Freeze (32°F) | Jun 17 | May 31 | May 4 |
| Hard (28°F) | Jun 4 | May 9 | Apr 21 |
| Severe (24°F) | May 16 | Apr 24 | Apr 3 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 28 | Jun 23 | Jun 19 | Jun 15 | Jun 12 | Jun 9 | Jun 5 | Jun 1 | May 22 |
| 32°F | Jun 17 | Jun 11 | Jun 6 | Jun 3 | May 31 | May 23 | May 18 | May 12 | May 4 |
| 28°F | Jun 4 | May 28 | May 20 | May 15 | May 9 | May 3 | Apr 30 | Apr 26 | Apr 21 |
| 24°F | May 16 | May 6 | May 1 | Apr 27 | Apr 24 | Apr 20 | Apr 16 | Apr 11 | Apr 3 |
| 20°F | Apr 30 | Apr 19 | Apr 14 | Apr 10 | Apr 5 | Apr 1 | Mar 26 | Mar 17 | Mar 8 |
| 16°F | Apr 6 | Mar 31 | Mar 26 | Mar 18 | Mar 10 | Mar 5 | Mar 1 | Feb 24 | Feb 17 |
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 26 | Oct 12 |
| Freeze (32°F) | Sep 10 | Oct 6 | Oct 25 |
| Hard (28°F) | Sep 29 | Oct 19 | Nov 6 |
| Severe (24°F) | Oct 12 | Oct 31 | Nov 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 3 | Sep 11 | Sep 18 | Sep 22 | Sep 26 | Sep 29 | Oct 2 | Oct 6 | Oct 12 |
| 32°F | Sep 10 | Sep 23 | Sep 28 | Oct 2 | Oct 6 | Oct 10 | Oct 14 | Oct 19 | Oct 25 |
| 28°F | Sep 29 | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Nov 1 | Nov 6 |
| 24°F | Oct 12 | Oct 18 | Oct 22 | Oct 27 | Oct 31 | Nov 3 | Nov 6 | Nov 11 | Nov 17 |
| 20°F | Oct 22 | Oct 29 | Nov 2 | Nov 6 | Nov 10 | Nov 14 | Nov 17 | Nov 22 | Nov 28 |
| 16°F | Oct 31 | Nov 7 | Nov 13 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 4 | Dec 12 |
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: Silver City 5 W, Id, about 11.2 miles away@if(!empty($station['elevation_ft'])), at 6,160 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 Jordan Valley, ID?
On average, the last spring frost (32°F) around Jordan Valley, ID is about May 31. In cooler years it can run later, so for a safer bet many gardeners wait until May 4.
When is the first frost in the fall?
The first fall frost around Jordan Valley, ID typically arrives about Oct 6. 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 4 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 128 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 83650 Planting calendar → Idaho frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026