Last frost date in Napa, CA
Expect the last frost in Napa around February 12. Frost after March 13 happens in only one year out of ten. The first fall frost usually arrives about December 4, which leaves 299 frost-free days. An early freeze before November 15 happens one year in ten.
- Safe after (10% risk)
- Mar 13
- Average first frost
- Dec 4
- Frost-free season
- 299 days
- Hard freeze (28°F) ends
- Jan 11
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2246°
- FriOct 2344°
- SatOct 2443°
- SunOct 2545°
- MonOct 2645°
- TueOct 2746°
Planting calendar for Napa
Windows count forward or back from the average frost dates above. Click a crop for dates across California.
TomatoesFeb 19–Mar 5
PumpkinsFeb 26–Mar 12
SunflowersFeb 15–Mar 8
CucumbersFeb 26–Mar 5
CornFeb 19–Mar 5
Sweet potatoesMar 5–Mar 19
WatermelonFeb 26–Mar 12
Green beansFeb 19–Mar 12
ZucchiniFeb 19–Mar 5
OkraMar 5–Mar 19
PeppersFeb 26–Mar 12
BasilFeb 19–Mar 5
Butternut squashFeb 19–Mar 5
CantaloupeFeb 26–Mar 12
EggplantFeb 26–Mar 12
PotatoesJan 15–Jan 29
OnionsJan 1–Jan 22
CarrotsJan 22–Feb 26
LettuceJan 29–Feb 19
BroccoliJan 15–Jan 29
BeetsJan 15–Feb 26
PeasJan 1–Jan 15
CabbageJan 15–Jan 29
RadishesJan 8–Feb 19
Brussels sproutsJan 29–Feb 12
SpinachJan 1–Jan 22
CilantroJan 29–Feb 19
KaleJan 15–Jan 29
Collard greensJan 15–Jan 29
TurnipsJan 15–Jan 29
DillFeb 12–Feb 26
CeleryFeb 19–Feb 26
CauliflowerJan 29–Feb 12
LeeksJan 29–Feb 12
Swiss chardJan 29–Feb 26
ParsleyJan 29–Feb 19
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesJan 15–Jan 29
AsparagusJan 15–Jan 29Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Jan 3 | Feb 12 | Mar 13 | Nov 15 | Dec 4 | Jan 4 |
| Hard freeze, 28°F | Dec 16 | Jan 11 | Feb 13 | Dec 1 | Dec 19 | Jan 23 |
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 Napa State Hospital (USC00046074) sits 2.4 miles from the center of Napa at 35 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 Napa, CA?
The average last frost date in Napa is February 12, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 13.
When is the first frost in Napa?
The first frost in fall usually comes around December 4. One year in ten it arrives before November 15.
How long is the growing season in Napa?
About 299 days between the average last and first frost.
When should I plant tomatoes in Napa?
Plant tomato seedlings outside from February 19 to March 5. Start seeds indoors six to eight weeks earlier.
Nearby in California
- American CanyonMar 5
- VallejoJan 17
- FairfieldJan 15
- Suisun CityJan 15
- BeniciaJan 17
- PetalumaFeb 28
- VacavilleFeb 18
- HerculesJan 17
- NovatoJan 11
- Rohnert ParkFeb 25
- MartinezFeb 28
- San PabloJan 4