Last spring frost
May 16
Frost Dates for Inkom, ID
First fall frost
Oct 2
Growing season
137 days
Hardiness zone
6a
In an average year around Inkom, ID, the last spring frost (32°F) is about May 16 and the first fall frost is about Oct 2, giving roughly a 137-day growing season. To be safe most years, wait until Apr 30 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 18 | Jun 5 | May 17 |
| Freeze (32°F) | Jun 6 | May 16 | Apr 30 |
| Hard (28°F) | May 18 | May 1 | Apr 16 |
| Severe (24°F) | May 5 | Apr 17 | Mar 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 18 | Jun 14 | Jun 10 | Jun 7 | Jun 5 | Jun 2 | May 28 | May 22 | May 17 |
| 32°F | Jun 6 | May 31 | May 25 | May 20 | May 16 | May 12 | May 8 | May 4 | Apr 30 |
| 28°F | May 18 | May 12 | May 7 | May 3 | May 1 | Apr 28 | Apr 24 | Apr 20 | Apr 16 |
| 24°F | May 5 | Apr 30 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 6 | Apr 2 | Mar 25 |
| 20°F | Apr 19 | Apr 11 | Apr 5 | Mar 31 | Mar 28 | Mar 22 | Mar 17 | Mar 10 | Mar 3 |
| 16°F | Mar 30 | Mar 24 | Mar 17 | Mar 11 | Mar 8 | Mar 4 | Feb 28 | Feb 23 | Feb 16 |
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 5 | Sep 21 | Oct 4 |
| Freeze (32°F) | Sep 14 | Oct 2 | Oct 18 |
| Hard (28°F) | Sep 26 | Oct 13 | Oct 29 |
| Severe (24°F) | Oct 6 | Oct 25 | Nov 12 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 10 | Sep 14 | Sep 19 | Sep 21 | Sep 24 | Sep 26 | Sep 29 | Oct 4 |
| 32°F | Sep 14 | Sep 21 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 9 | Oct 13 | Oct 18 |
| 28°F | Sep 26 | Oct 3 | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 24 | Oct 29 |
| 24°F | Oct 6 | Oct 12 | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 5 | Nov 12 |
| 20°F | Oct 19 | Oct 25 | Oct 30 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 18 | Nov 24 |
| 16°F | Oct 27 | Nov 3 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 26 | Dec 2 |
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: Pocatello 2 Ne, Id, about 11.4 miles away@if(!empty($station['elevation_ft'])), at 4,832 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 Inkom, ID?
On average, the last spring frost (32°F) around Inkom, ID is about May 16. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 30.
When is the first frost in the fall?
The first fall frost around Inkom, ID typically arrives about Oct 2. 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 16 on average, or Apr 30 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 137 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 83245 Planting calendar → Idaho frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026