USDA Hardiness Zone 10b
Frost Dates for 92093 — La Jolla, California
NOAA 1991–2020 normals from Ramona Fire Dept, CA (1,470 ft), 4 miles west.
Updated
In La Jolla, the last spring frost (32°F) is around March 4 in half of years and has passed by April 10 in nine years out of ten. The first fall frost comes around December 4, as early as November 17 one year in ten, leaving a typical freeze-free season of 270 days (NOAA, Ramona Fire Dept, CA).
- Last spring frost
- March 4
- First fall frost
- December 4
- Growing season
- 270 days
- Hardiness zone
- 10b
50% probability
50% probability
freeze-free, 50%
35 to 40°F (1.7 to 4.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 18 observed
NOAA normal
Frost risk by date in La Jolla
Half of springs at Ramona Fire Dept, CA see their last 32°F night by March 4; only one in ten is past it by January 29, and one in ten still has one after April 10. Planting tender crops after March 23 leaves a 30% risk of a frost on them, after March 31 20%, and after April 10 10%. The 37 days between the even-odds date and the one-in-ten date is wider than at 79% of the 220 California stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by December 4 in half of years, as early as November 17 one year in ten, and holds off past December 18 one year in ten. A hard freeze of 28°F follows 15 days later, around December 19; in spring the one-in-ten date for 28°F is March 1, 40 days before the 32°F one. The freeze-free season lasts 270 days in a typical year, shorter than at 58% of the 219 California stations; it reaches 308 days one year in ten and falls short of 234 one year in ten. On average 28 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 37 days longer, to about April 10, and return around November 19. A 24°F night is unusual: 38% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 17 | Mar 30 | Apr 3 | Apr 6 | Apr 10 | Apr 13 | Apr 17 | Apr 21 | Apr 28 |
| 32°F | Jan 29 | Feb 13 | Feb 21 | Feb 27 | Mar 4 | Mar 11 | Mar 23 | Mar 31 | Apr 10 |
| 28°F92% of yrs | Dec 23 | Dec 31 | Jan 11 | Jan 20 | Jan 31 | Feb 8 | Feb 15 | Feb 23 | Mar 1 |
| 24°F38% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 26 | Nov 3 | Nov 9 | Nov 14 | Nov 19 | Nov 22 | Nov 26 | Dec 1 | Dec 4 |
| 32°F | Nov 17 | Nov 25 | Nov 30 | Dec 2 | Dec 4 | Dec 7 | Dec 11 | Dec 14 | Dec 18 |
| 28°F92% of yrs | Dec 1 | Dec 8 | Dec 12 | Dec 16 | Dec 19 | Dec 23 | Dec 27 | Jan 2 | Jan 16 |
| 24°F38% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Ramona Fire Dept, 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 92093 →Compare La Jolla with another place →
Weather by month in La Jolla
August is the warmest month at Ramona Fire Dept, CA, averaging 92°F by day and 59°F at night; December is the coldest at 67°F and 37°F. A freezing night is all but certain in every month from December to January (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 77% of years and March still brings one in 45% of years and April still brings one in 20% of years.
Warmth for growing adds up to 4,659 growing degree days a year (base 50°F), more than at 52% of the 283 California stations. 34% of them (1,602) have built up by the end of June, and August adds the most, 798. Precipitation totals 14.5 inches a year, most in February (3.5") and least in June (0.1"); May to September bring 6% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 68 | 38 | 3.1 | 91% | 7 | 114 |
| Feb | 68 | 39 | 3.5 | 77% | 5 | 113 |
| Mar | 69 | 41 | 2.7 | 45% | 2 | 172 |
| Apr | 73 | 43 | 1.1 | 20% | 1 | 253 |
| May | 77 | 49 | 0.4 | 0% | 0 | 402 |
| Jun | 85 | 52 | 0.1 | 0% | 0 | 549 |
| Jul | 90 | 57 | 0.1 | 0% | 0 | 735 |
| Aug | 92 | 59 | 0.1 | 0% | 0 | 798 |
| Sep | 90 | 55 | 0.2 | 0% | 0 | 679 |
| Oct | 82 | 49 | 0.5 | 2% | <1 | 481 |
| Nov | 74 | 43 | 1.2 | 31% | 3 | 269 |
| Dec | 67 | 37 | 1.5 | 98% | 10 | 96 |
Monthly normals 1991–2020 at Ramona Fire Dept, CA (1,470 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Alpine, CA, 13 miles south of La Jolla and 225 feet higher, has a last frost 20 days earlier (February 12), a first frost 20 days later (December 24), a season 47 days longer.
When it snows in La Jolla, California
Measurable snow is rare here: only 0 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Ramona Fire Dept, CA, 3.6 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 92093
| When | What to do |
|---|---|
| December 24 – January 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 7 – January 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 4 – February 18 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 4 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 20 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 4 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 92093 is 4 miles from Ramona Fire Dept, CA, which stands at 1,470 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 92058 (Oceanside). The 2023 USDA Plant Hardiness Zone Map lists ZIP 92093 in zone 10b, the band where the coldest night of the year averaged 35 to 40°F (1.7 to 4.4°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.