Last spring frost
May 14
Frost Dates for Kellogg, ID
First fall frost
Sep 26
Growing season
131 days
Hardiness zone
6b
In an average year around Kellogg, ID, the last spring frost (32°F) is about May 14 and the first fall frost is about Sep 26, giving roughly a 131-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 24 | Jun 2 | May 16 |
| Freeze (32°F) | Jun 3 | May 14 | Apr 30 |
| Hard (28°F) | May 13 | Apr 30 | Apr 12 |
| Severe (24°F) | Apr 29 | Apr 7 | Mar 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 24 | Jun 16 | Jun 11 | Jun 6 | Jun 2 | May 30 | May 27 | May 22 | May 16 |
| 32°F | Jun 3 | May 26 | May 21 | May 17 | May 14 | May 11 | May 8 | May 4 | Apr 30 |
| 28°F | May 13 | May 9 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 23 | Apr 18 | Apr 12 |
| 24°F | Apr 29 | Apr 21 | Apr 15 | Apr 10 | Apr 7 | Apr 2 | Mar 30 | Mar 24 | Mar 18 |
| 20°F | Apr 3 | Mar 28 | Mar 22 | Mar 18 | Mar 14 | Mar 10 | Mar 7 | Mar 3 | Feb 25 |
| 16°F | Mar 17 | Mar 12 | Mar 8 | Mar 5 | Mar 2 | Feb 28 | Feb 22 | Feb 16 | Feb 8 |
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 26 | Sep 10 | Sep 26 |
| Freeze (32°F) | Sep 9 | Sep 26 | Oct 9 |
| Hard (28°F) | Sep 24 | Oct 8 | Oct 24 |
| Severe (24°F) | Oct 6 | Oct 24 | Nov 13 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 26 | Sep 1 | Sep 4 | Sep 7 | Sep 10 | Sep 14 | Sep 17 | Sep 22 | Sep 26 |
| 32°F | Sep 9 | Sep 15 | Sep 19 | Sep 23 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 9 |
| 28°F | Sep 24 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 16 | Oct 20 | Oct 24 |
| 24°F | Oct 6 | Oct 13 | Oct 17 | Oct 21 | Oct 24 | Oct 28 | Nov 1 | Nov 6 | Nov 13 |
| 20°F | Oct 18 | Oct 24 | Oct 29 | Nov 2 | Nov 8 | Nov 12 | Nov 17 | Nov 22 | Nov 29 |
| 16°F | Oct 28 | Nov 5 | Nov 12 | Nov 18 | Nov 23 | Nov 28 | Dec 1 | Dec 6 | Dec 16 |
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: Kellogg, Id, about 1.5 miles away@if(!empty($station['elevation_ft'])), at 2,377 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 Kellogg, ID?
On average, the last spring frost (32°F) around Kellogg, ID is about May 14. 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 Kellogg, ID typically arrives about Sep 26. 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 14 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 131 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 83837 Planting calendar → Idaho frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026