Last spring frost
May 12
Frost Dates for Sierra City, CA
First fall frost
Oct 29
Growing season
167 days
Hardiness zone
7a
In an average year around Sierra City, CA, the last spring frost (32°F) is about May 12 and the first fall frost is about Oct 29, giving roughly a 167-day growing season. To be safe most years, wait until Apr 22 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 17 | May 31 | May 9 |
| Freeze (32°F) | Jun 2 | May 12 | Apr 22 |
| Hard (28°F) | May 19 | Apr 23 | Apr 4 |
| Severe (24°F) | Apr 29 | Apr 6 | Mar 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 17 | Jun 10 | Jun 5 | Jun 2 | May 31 | May 27 | May 22 | May 16 | May 9 |
| 32°F | Jun 2 | May 28 | May 23 | May 17 | May 12 | May 7 | May 2 | Apr 27 | Apr 22 |
| 28°F | May 19 | May 10 | May 3 | Apr 28 | Apr 23 | Apr 19 | Apr 15 | Apr 10 | Apr 4 |
| 24°F | Apr 29 | Apr 20 | Apr 15 | Apr 10 | Apr 6 | Apr 1 | Mar 26 | Mar 20 | Mar 14 |
| 20°F | Apr 10 | Apr 3 | Mar 26 | Mar 17 | Mar 12 | Mar 6 | Feb 28 | Feb 21 | Feb 8 |
| 16°F | Mar 24 | Mar 6 | Feb 28 | Feb 22 | Feb 14 | Feb 6 | Jan 30 | Jan 17 | Jan 5 |
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 19 | Oct 11 | Oct 29 |
| Freeze (32°F) | Oct 10 | Oct 29 | Nov 13 |
| Hard (28°F) | Oct 27 | Nov 13 | Nov 30 |
| Severe (24°F) | Nov 10 | Nov 28 | Dec 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 19 | Sep 29 | Oct 4 | Oct 8 | Oct 11 | Oct 15 | Oct 18 | Oct 23 | Oct 29 |
| 32°F | Oct 10 | Oct 16 | Oct 20 | Oct 25 | Oct 29 | Nov 1 | Nov 4 | Nov 8 | Nov 13 |
| 28°F | Oct 27 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 30 |
| 24°F | Nov 10 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 9 | Dec 14 |
| 20°F | Nov 21 | Nov 29 | Dec 3 | Dec 8 | Dec 13 | Dec 16 | Dec 21 | Dec 27 | Jan 7 |
| 16°F | Dec 1 | Dec 11 | Dec 18 | Dec 25 | Jan 1 | Jan 5 | Jan 13 | Jan 22 | Feb 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: Bowman Dam, Ca, about 11.4 miles away@if(!empty($station['elevation_ft'])), at 5,385 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 Sierra City, CA?
On average, the last spring frost (32°F) around Sierra City, CA is about May 12. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 22.
When is the first frost in the fall?
The first fall frost around Sierra City, CA typically arrives about Oct 29. 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 12 on average, or Apr 22 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 167 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 96125 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026