USDA Hardiness Zone 9a
Frost Dates for 93240 — Lake Isabella, California
NOAA 1991–2020 normals from S Lake Fs, CA (2,654 ft), 6 miles east.
Updated
In Lake Isabella, the last spring frost (32°F) is around April 5 in half of years and has passed by April 21 in nine years out of ten. The first fall frost comes around November 3, as early as October 18 one year in ten, leaving a typical freeze-free season of 212 days (NOAA, S Lake Fs, CA).
- Last spring frost
- April 5
- First fall frost
- November 3
- Growing season
- 212 days
- Hardiness zone
- 9a
50% probability
50% probability
freeze-free, 50%
20 to 25°F (-6.7 to -3.9°C) coldest night
- First snow
- December 24
- Last snow
- February 20
- Winters with snow
- 90%
- Snow per year
- 6.2"
median, 1991–2020
median, 1991–2020
18 of 20 observed
NOAA normal
Frost risk by date in Lake Isabella
Half of springs at S Lake Fs, CA see their last 32°F night by April 5; only one in ten is past it by March 8, and one in ten still has one after April 21. Planting tender crops after April 12 leaves a 30% risk of a frost on them, after April 16 20%, and after April 21 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 98% of the 220 California stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 3 in half of years, as early as October 18 one year in ten, and holds off past November 16 one year in ten. A hard freeze of 28°F follows 14 days later, around November 17; in spring the one-in-ten date for 28°F is April 7, 14 days before the 32°F one. The freeze-free season lasts 212 days in a typical year, shorter than at 78% of the 219 California stations; it reaches 241 days one year in ten and falls short of 189 one year in ten. On average 80 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 15 days longer, to about April 20, and return around October 21. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 16%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 26 | Apr 29 | May 1 |
| 32°F | Mar 8 | Mar 16 | Mar 22 | Mar 30 | Apr 5 | Apr 9 | Apr 12 | Apr 16 | Apr 21 |
| 28°F | Feb 8 | Feb 18 | Feb 24 | Mar 1 | Mar 6 | Mar 11 | Mar 18 | Mar 30 | Apr 7 |
| 24°F99% of yrs | Jan 2 | Jan 12 | Jan 20 | Jan 29 | Feb 4 | Feb 9 | Feb 16 | Feb 23 | Mar 3 |
| 20°F70% of yrs | Dec 11 | Dec 22 | Dec 29 | Jan 1 | Jan 6 | Jan 11 | Jan 17 | Jan 27 | Feb 6 |
| 16°F16% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 9 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 28 | Nov 1 | Nov 5 |
| 32°F | Oct 18 | Oct 22 | Oct 28 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 |
| 28°F | Oct 31 | Nov 5 | Nov 9 | Nov 13 | Nov 17 | Nov 20 | Nov 23 | Nov 27 | Dec 1 |
| 24°F99% of yrs | Nov 15 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 5 | Dec 9 | Dec 15 | Dec 24 |
| 20°F70% of yrs | Nov 27 | Dec 2 | Dec 8 | Dec 12 | Dec 19 | Dec 24 | Dec 31 | Jan 5 | Jan 18 |
| 16°F16% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at S Lake Fs, CA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 93240 →Compare Lake Isabella with another place →
Compared with the next station
The nearest other station, Kern River Ph 3, CA, 11 miles north of Lake Isabella, has a last frost 2 days later (April 7), a first frost 8 days later (November 11), a season 5 days longer.
When it snows in Lake Isabella, California
The first measurable snow (0.1 inch or more) in Lake Isabella usually arrives around December 24, and the last of the season around February 20. Those are the middle dates across the winters of 1991–2020 at Glennville, CA, 15.8 miles away: half of years saw snow earlier, half later. Snow fell in 90% of those winters. The last 32°F night of spring typically comes 44 days after the last snow.
Planting calendar for 93240
| When | What to do |
|---|---|
| January 25 – February 8 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 8 – February 22 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 8 – March 22 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 5 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 20 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 3 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 93240 is 6 miles from S Lake Fs, CA, which stands at 2,654 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 93240 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across California →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.