Last spring frost
May 5
Frost Dates for Lake Arrowhead, CA
First fall frost
Nov 2
Growing season
176 days
Hardiness zone
8a
In an average year around Lake Arrowhead, CA, the last spring frost (32°F) is about May 5 and the first fall frost is about Nov 2, giving roughly a 176-day growing season. To be safe most years, wait until Apr 9 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 10 | May 27 | May 3 |
| Freeze (32°F) | May 31 | May 5 | Apr 9 |
| Hard (28°F) | May 12 | Apr 11 | Mar 14 |
| Severe (24°F) | Apr 10 | Mar 16 | Feb 10 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 10 | Jun 4 | Jun 2 | May 31 | May 27 | May 23 | May 18 | May 12 | May 3 |
| 32°F | May 31 | May 25 | May 18 | May 11 | May 5 | Apr 30 | Apr 26 | Apr 19 | Apr 9 |
| 28°F | May 12 | May 1 | Apr 24 | Apr 17 | Apr 11 | Apr 6 | Mar 31 | Mar 24 | Mar 14 |
| 24°F | Apr 10 | Apr 3 | Mar 29 | Mar 21 | Mar 16 | Mar 9 | Mar 2 | Feb 25 | Feb 10 |
| 20°F | Mar 23 | Mar 10 | Feb 28 | Feb 22 | Feb 11 | Feb 2 | Jan 25 | Jan 13 | Dec 31 |
| 16°F | Feb 28 | Feb 12 | Feb 1 | Jan 21 | Jan 12 | Jan 6 | Jan 1 | Dec 25 | Dec 14 |
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 30 | Oct 18 | Nov 5 |
| Freeze (32°F) | Oct 12 | Nov 2 | Nov 15 |
| Hard (28°F) | Oct 31 | Nov 16 | Nov 30 |
| Severe (24°F) | Nov 13 | Dec 1 | Dec 21 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 5 | Oct 10 | Oct 13 | Oct 18 | Oct 23 | Oct 28 | Nov 1 | Nov 5 |
| 32°F | Oct 12 | Oct 19 | Oct 25 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 15 |
| 28°F | Oct 31 | Nov 5 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 30 |
| 24°F | Nov 13 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 21 |
| 20°F | Nov 27 | Dec 3 | Dec 9 | Dec 14 | Dec 20 | Dec 25 | Dec 30 | Jan 9 | Jan 25 |
| 16°F | Dec 6 | Dec 14 | Dec 22 | Dec 28 | Jan 1 | Jan 8 | Jan 15 | Jan 29 | Feb 13 |
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: Lake Arrowhead, Ca, about 2.3 miles away@if(!empty($station['elevation_ft'])), at 5,205 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 Lake Arrowhead, CA?
On average, the last spring frost (32°F) around Lake Arrowhead, CA is about May 5. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 9.
When is the first frost in the fall?
The first fall frost around Lake Arrowhead, CA typically arrives about Nov 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 5 on average, or Apr 9 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 176 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 92378 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026