Last frost date in San Marcos, CA
The average last frost in San Marcos is January 2. By February 4 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about December 30, which leaves 365 frost-free days. An early freeze before December 8 happens one year in ten.
- Safe after (10% risk)
- Feb 4
- Average first frost
- Dec 30
- Frost-free season
- 365 days
- Hard freeze (28°F) ends
- rare
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2257°
- FriOct 2356°
- SatOct 2458°
- SunOct 2559°
- MonOct 2659°
- TueOct 2759°
Planting calendar for San Marcos
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 5–Dec 19
OnionsNov 21–Dec 12
CarrotsDec 12–Jan 16
LettuceDec 19–Jan 9
BroccoliDec 5–Dec 19
BeetsDec 5–Jan 16
PeasNov 21–Dec 5
CabbageDec 5–Dec 19
RadishesNov 28–Jan 9
Brussels sproutsDec 19–Jan 2
SpinachNov 21–Dec 12
CilantroDec 19–Jan 9
KaleDec 5–Dec 19
Collard greensDec 5–Dec 19
TurnipsDec 5–Dec 19
DillJan 2–Jan 16
CeleryJan 9–Jan 16
CauliflowerDec 19–Jan 2
LeeksDec 19–Jan 2
Swiss chardDec 19–Jan 16
ParsleyDec 19–Jan 9
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesDec 5–Dec 19
AsparagusDec 5–Dec 19Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Dec 14 | Jan 2 | Feb 4 | Dec 8 | Dec 30 | Jan 29 |
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 Escondido #2 (USC00042863) sits 4.7 miles from the center of San Marcos at 600 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 San Marcos, CA?
The average last frost date in San Marcos is January 2, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after February 4.
When is the first frost in San Marcos?
The first frost in fall usually comes around December 30. One year in ten it arrives before December 8.
How long is the growing season in San Marcos?
About 365 days between the average last and first frost.
When should I plant tomatoes in San Marcos?
Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.