Last spring frost
May 29
Frost Dates for Hat Creek, CA
First fall frost
Sep 19
Growing season
113 days
Hardiness zone
7a
In an average year around Hat Creek, CA, the last spring frost (32°F) is about May 29 and the first fall frost is about Sep 19, giving roughly a 113-day growing season. To be safe most years, wait until May 8 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%) |
|---|---|---|---|
| Freeze (32°F) | Jun 23 | May 29 | May 8 |
| Hard (28°F) | Jun 3 | May 6 | Apr 19 |
| Severe (24°F) | May 12 | Apr 19 | Mar 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 32°F | Jun 23 | Jun 13 | Jun 6 | Jun 2 | May 29 | May 24 | May 18 | May 13 | May 8 |
| 28°F | Jun 3 | May 22 | May 15 | May 10 | May 6 | May 3 | Apr 30 | Apr 26 | Apr 19 |
| 24°F | May 12 | May 2 | Apr 27 | Apr 22 | Apr 19 | Apr 13 | Apr 8 | Apr 3 | Mar 28 |
| 20°F | Apr 21 | Apr 10 | Apr 3 | Mar 29 | Mar 23 | Mar 17 | Mar 11 | Mar 6 | Feb 26 |
| 16°F | Mar 13 | Mar 6 | Mar 2 | Feb 27 | Feb 21 | Feb 17 | Feb 11 | Feb 4 | Jan 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%) |
|---|---|---|---|
| Freeze (32°F) | Sep 5 | Sep 19 | Oct 4 |
| Hard (28°F) | Sep 19 | Oct 4 | Oct 22 |
| Severe (24°F) | Oct 3 | Oct 20 | Nov 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 32°F | Sep 5 | Sep 10 | Sep 14 | Sep 17 | Sep 19 | Sep 22 | Sep 25 | Sep 29 | Oct 4 |
| 28°F | Sep 19 | Sep 26 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 11 | Oct 16 | Oct 22 |
| 24°F | Oct 3 | Oct 9 | Oct 13 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Nov 1 | Nov 7 |
| 20°F | Oct 16 | Oct 22 | Oct 27 | Nov 1 | Nov 3 | Nov 7 | Nov 11 | Nov 18 | Nov 24 |
| 16°F | Oct 30 | Nov 5 | Nov 10 | Nov 14 | Nov 19 | Nov 24 | Nov 28 | Dec 3 | Dec 11 |
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: Hat Creek, Ca, about 10.4 miles away@if(!empty($station['elevation_ft'])), at 3,015 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 Hat Creek, CA?
On average, the last spring frost (32°F) around Hat Creek, CA is about May 29. In cooler years it can run later, so for a safer bet many gardeners wait until May 8.
When is the first frost in the fall?
The first fall frost around Hat Creek, CA typically arrives about Sep 19. 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 29 on average, or May 8 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 113 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 96040 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026