Last frost date in Rancho San Diego, CA
The average last frost in Rancho San Diego is January 6. By February 7 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about December 21, which leaves 350 frost-free days. An early freeze before December 1 happens one year in ten.
- Safe after (10% risk)
- Feb 7
- Average first frost
- Dec 21
- Frost-free season
- 350 days
- Hard freeze (28°F) ends
- Dec 31
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2256°
- FriOct 2354°
- SatOct 2456°
- SunOct 2557°
- MonOct 2657°
- TueOct 2758°
Planting calendar for Rancho San Diego
Windows count forward or back from the average frost dates above. Click a crop for dates across California.
TomatoesFeb 15–Mar 1
PumpkinsFeb 15–Mar 1
SunflowersFeb 15–Mar 8
CucumbersFeb 22–Mar 1
CornFeb 15–Mar 1
Sweet potatoesFeb 15–Mar 1
WatermelonFeb 15–Mar 1
Green beansFeb 15–Mar 8
ZucchiniFeb 15–Mar 1
OkraFeb 15–Mar 1
PeppersFeb 15–Mar 1
BasilFeb 15–Mar 1
Butternut squashFeb 15–Mar 1
CantaloupeFeb 15–Mar 1
EggplantFeb 15–Mar 1
PotatoesDec 9–Dec 23
OnionsNov 25–Dec 16
CarrotsDec 16–Jan 20
LettuceDec 23–Jan 13
BroccoliDec 9–Dec 23
BeetsDec 9–Jan 20
PeasNov 25–Dec 9
CabbageDec 9–Dec 23
RadishesDec 2–Jan 13
Brussels sproutsDec 23–Jan 6
SpinachNov 25–Dec 16
CilantroDec 23–Jan 13
KaleDec 9–Dec 23
Collard greensDec 9–Dec 23
TurnipsDec 9–Dec 23
DillJan 6–Jan 20
CeleryJan 13–Jan 20
CauliflowerDec 23–Jan 6
LeeksDec 23–Jan 6
Swiss chardDec 23–Jan 20
ParsleyDec 23–Jan 13
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesDec 9–Dec 23
AsparagusDec 9–Dec 23Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Dec 13 | Jan 6 | Feb 7 | Dec 1 | Dec 21 | Jan 15 |
| Hard freeze, 28°F | Dec 8 | Dec 31 | Jan 15 | Dec 7 | Dec 30 | Jan 14 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station El Cajon (USC00042706) sits 2.7 miles from the center of Rancho San Diego at 495 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Rancho San Diego, CA?
The average last frost date in Rancho San Diego is January 6, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after February 7.
When is the first frost in Rancho San Diego?
The first frost in fall usually comes around December 21. One year in ten it arrives before December 1.
How long is the growing season in Rancho San Diego?
About 350 days between the average last and first frost.
When should I plant tomatoes in Rancho San Diego?
Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.
Nearby in California
- El CajonJan 6
- Spring ValleyJan 6
- Winter GardensJan 6
- La MesaJan 6
- La Presano frost
- LakesideJan 6
- Lemon Groveno frost
- SanteeJan 6
- Chula Vistano frost
- National Cityno frost
- San Diegono frost
- Coronadono frost