Last frost date in American Canyon, CA

Average last frost
March 5

The average last frost in American Canyon is March 5. By April 16 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about November 21, which leaves 256 frost-free days. An early freeze before November 3 happens one year in ten.

Safe after (10% risk)
Apr 16
Average first frost
Nov 21
Frost-free season
256 days
Hard freeze (28°F) ends
Jan 23
Next 6 nights in American Canyon

No frost in the next 6 nights

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2249°
  2. FriOct 2346°
  3. SatOct 2446°
  4. SunOct 2548°
  5. MonOct 2648°
  6. TueOct 2748°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Mar 5First frost Nov 21256 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND256 frost-free days
Frost risk through the year at Napa County Airport, 2.6 miles from American Canyon.

Planting calendar for American Canyon

Windows count forward or back from the average frost dates above. Click a crop for dates across California.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMar 12–Mar 26
PumpkinsMar 19–Apr 2
SunflowersMar 5–Mar 26
CucumbersMar 19–Mar 26
CornMar 12–Mar 26
Sweet potatoesMar 26–Apr 9
WatermelonMar 19–Apr 2
Green beansMar 12–Apr 2
ZucchiniMar 12–Mar 26
OkraMar 26–Apr 9
PeppersMar 19–Apr 2
BasilMar 12–Mar 26
Butternut squashMar 12–Mar 26
CantaloupeMar 19–Apr 2
EggplantMar 19–Apr 2
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesFeb 5–Feb 19
OnionsJan 22–Feb 12
CarrotsFeb 12–Mar 19
LettuceFeb 19–Mar 12
BroccoliFeb 5–Feb 19
BeetsFeb 5–Mar 19
PeasJan 22–Feb 5
CabbageFeb 5–Feb 19
RadishesJan 29–Mar 12
Brussels sproutsFeb 19–Mar 5
SpinachJan 22–Feb 12
CilantroFeb 19–Mar 12
KaleFeb 5–Feb 19
Collard greensFeb 5–Feb 19
TurnipsFeb 5–Feb 19
DillMar 5–Mar 19
CeleryMar 12–Mar 19
CauliflowerFeb 19–Mar 5
LeeksFeb 19–Mar 5
Swiss chardFeb 19–Mar 19
ParsleyFeb 19–Mar 12
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsNov 7–Dec 12
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesFeb 5–Feb 19
AsparagusFeb 5–Feb 19

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FJan 26Mar 5Apr 16Nov 3Nov 21Dec 13
Hard freeze, 28°FDec 20Jan 23Feb 28Nov 16Dec 5Jan 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 Napa County Airport (USW00093227) sits 2.6 miles from the center of American Canyon at 14 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 American Canyon, CA?

The average last frost date in American Canyon is March 5, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 16.

When is the first frost in American Canyon?

The first frost in fall usually comes around November 21. One year in ten it arrives before November 3.

How long is the growing season in American Canyon?

About 256 days between the average last and first frost.

When should I plant tomatoes in American Canyon?

Plant tomato seedlings outside from March 12 to March 26. Start seeds indoors six to eight weeks earlier.

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