Last spring frost
Apr 10
Frost Dates for Clearlake, CA
First fall frost
Nov 6
Growing season
209 days
Hardiness zone
9a
In an average year around Clearlake, CA, the last spring frost (32°F) is about Apr 10 and the first fall frost is about Nov 6, giving roughly a 209-day growing season. To be safe most years, wait until Mar 24 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) | May 16 | Apr 30 | Apr 14 |
| Freeze (32°F) | Apr 30 | Apr 10 | Mar 24 |
| Hard (28°F) | Apr 7 | Mar 14 | Feb 12 |
| Severe (24°F) | Mar 8 | Feb 7 | Dec 29 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 16 | May 10 | May 6 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 14 |
| 32°F | Apr 30 | Apr 23 | Apr 18 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Mar 31 | Mar 24 |
| 28°F | Apr 7 | Mar 31 | Mar 27 | Mar 21 | Mar 14 | Mar 9 | Mar 2 | Feb 25 | Feb 12 |
| 24°F | Mar 8 | Feb 28 | Feb 23 | Feb 15 | Feb 7 | Jan 30 | Jan 22 | Jan 11 | Dec 29 |
| 20°F | Feb 14 | Feb 1 | Jan 26 | Jan 20 | Jan 11 | Jan 4 | Dec 29 | Dec 21 | Dec 11 |
| 16°F | Jan 25 | Jan 18 | Jan 11 | Jan 4 | Dec 31 | Dec 24 | Dec 18 | Dec 12 | Dec 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) | Oct 11 | Oct 27 | Nov 7 |
| Freeze (32°F) | Oct 24 | Nov 6 | Nov 20 |
| Hard (28°F) | Nov 4 | Nov 21 | Dec 8 |
| Severe (24°F) | Nov 17 | Dec 6 | Jan 11 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 11 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 7 |
| 32°F | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 11 | Nov 14 | Nov 20 |
| 28°F | Nov 4 | Nov 10 | Nov 13 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 8 |
| 24°F | Nov 17 | Nov 25 | Dec 1 | Dec 3 | Dec 6 | Dec 11 | Dec 18 | Dec 29 | Jan 11 |
| 20°F | Dec 1 | Dec 6 | Dec 11 | Dec 17 | Dec 22 | Dec 30 | Jan 4 | Jan 14 | Jan 30 |
| 16°F | Dec 5 | Dec 10 | Dec 13 | Dec 20 | Dec 26 | Dec 31 | Jan 3 | Jan 11 | Jan 23 |
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: Clearlake 4 Se, Ca, about 1 miles away@if(!empty($station['elevation_ft'])), at 1,349 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 Clearlake, CA?
On average, the last spring frost (32°F) around Clearlake, CA is about Apr 10. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 24.
When is the first frost in the fall?
The first fall frost around Clearlake, CA typically arrives about Nov 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 Apr 10 on average, or Mar 24 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 209 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 95457 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026