Last frost date in Hercules, CA
In Hercules, the last spring frost comes around January 17 in an average year. Wait until March 4 if you want 90% odds of no more frost. The first fall frost usually arrives about December 27, which leaves 346 frost-free days. An early freeze before December 4 happens one year in ten.
- Safe after (10% risk)
- Mar 4
- Average first frost
- Dec 27
- Frost-free season
- 346 days
- Hard freeze (28°F) ends
- Jan 5
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2255°
- FriOct 2352°
- SatOct 2453°
- SunOct 2553°
- MonOct 2653°
- TueOct 2753°
Planting calendar for Hercules
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 20–Jan 3
OnionsDec 6–Dec 27
CarrotsDec 27–Jan 31
LettuceJan 3–Jan 24
BroccoliDec 20–Jan 3
BeetsDec 20–Jan 31
PeasDec 6–Dec 20
CabbageDec 20–Jan 3
RadishesDec 13–Jan 24
Brussels sproutsJan 3–Jan 17
SpinachDec 6–Dec 27
CilantroJan 3–Jan 24
KaleDec 20–Jan 3
Collard greensDec 20–Jan 3
TurnipsDec 20–Jan 3
DillJan 17–Jan 31
CeleryJan 24–Jan 31
CauliflowerJan 3–Jan 17
LeeksJan 3–Jan 17
Swiss chardJan 3–Jan 31
ParsleyJan 3–Jan 24
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesDec 20–Jan 3
AsparagusDec 20–Jan 3Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Dec 23 | Jan 17 | Mar 4 | Dec 4 | Dec 27 | Feb 4 |
| Hard freeze, 28°F | Dec 19 | Jan 5 | Jan 19 | Dec 13 | Jan 2 | Jan 19 |
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 Vallejo (USC00049219) sits 7.8 miles from the center of Hercules at 341 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 Hercules, CA?
The average last frost date in Hercules is January 17, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 4.
When is the first frost in Hercules?
The first frost in fall usually comes around December 27. One year in ten it arrives before December 4.
How long is the growing season in Hercules?
About 346 days between the average last and first frost.
When should I plant tomatoes in Hercules?
Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.
Nearby in California
- San PabloJan 4
- VallejoJan 17
- RichmondJan 4
- El CerritoJan 3
- BeniciaJan 17
- MartinezFeb 28
- BerkeleyJan 3
- American CanyonMar 5
- San RafaelJan 11
- Pleasant HillJan 7
- LafayetteJan 7
- NovatoJan 11