Last frost date in Suisun City, CA
In Suisun City, the last spring frost comes around January 15 in an average year. Wait until February 16 if you want 90% odds of no more frost. The first fall frost usually arrives about December 14, which leaves 336 frost-free days. An early freeze before November 29 happens one year in ten.
- Safe after (10% risk)
- Feb 16
- Average first frost
- Dec 14
- Frost-free season
- 336 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 2251°
- FriOct 2350°
- SatOct 2448°
- SunOct 2550°
- MonOct 2650°
- TueOct 2750°
Planting calendar for Suisun City
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 18–Jan 1
OnionsDec 4–Dec 25
CarrotsDec 25–Jan 29
LettuceJan 1–Jan 22
BroccoliDec 18–Jan 1
BeetsDec 18–Jan 29
PeasDec 4–Dec 18
CabbageDec 18–Jan 1
RadishesDec 11–Jan 22
Brussels sproutsJan 1–Jan 15
SpinachDec 4–Dec 25
CilantroJan 1–Jan 22
KaleDec 18–Jan 1
Collard greensDec 18–Jan 1
TurnipsDec 18–Jan 1
DillJan 15–Jan 29
CeleryJan 22–Jan 29
CauliflowerJan 1–Jan 15
LeeksJan 1–Jan 15
Swiss chardJan 1–Jan 29
ParsleyJan 1–Jan 22
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesDec 18–Jan 1
AsparagusDec 18–Jan 1Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Dec 22 | Jan 15 | Feb 16 | Nov 29 | Dec 14 | Jan 9 |
| Hard freeze, 28°F | Dec 13 | Dec 31 | Jan 19 | Dec 6 | Dec 24 | Jan 11 |
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 Fairfield (USC00042934) sits 3.6 miles from the center of Suisun City at 40 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 Suisun City, CA?
The average last frost date in Suisun City is January 15, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after February 16.
When is the first frost in Suisun City?
The first frost in fall usually comes around December 14. One year in ten it arrives before November 29.
How long is the growing season in Suisun City?
About 336 days between the average last and first frost.
When should I plant tomatoes in Suisun City?
Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.