Last frost date in Simi Valley, CA

Average last frost
January 24

In Simi Valley, the last spring frost comes around January 24 in an average year. Wait until March 5 if you want 90% odds of no more frost. The first fall frost usually arrives about December 15, which leaves 329 frost-free days. An early freeze before November 27 happens one year in ten.

Safe after (10% risk)
Mar 5
Average first frost
Dec 15
Frost-free season
329 days
Hard freeze (28°F) ends
Dec 31
Next 6 nights in Simi Valley

No frost in the next 6 nights

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

  1. ThuOct 2248°
  2. FriOct 2350°
  3. SatOct 2451°
  4. SunOct 2555°
  5. MonOct 2655°
  6. TueOct 2754°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Jan 24First frost Dec 15329 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND329 frost-free days
Frost risk through the year at Woodland Hills Pierce College, 11.6 miles from Simi Valley.

Planting calendar for Simi Valley

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
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
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesDec 27–Jan 10
OnionsDec 13–Jan 3
CarrotsJan 3–Feb 7
LettuceJan 10–Jan 31
BroccoliDec 27–Jan 10
BeetsDec 27–Feb 7
PeasDec 13–Dec 27
CabbageDec 27–Jan 10
RadishesDec 20–Jan 31
Brussels sproutsJan 10–Jan 24
SpinachDec 13–Jan 3
CilantroJan 10–Jan 31
KaleDec 27–Jan 10
Collard greensDec 27–Jan 10
TurnipsDec 27–Jan 10
DillJan 24–Feb 7
CeleryJan 31–Feb 7
CauliflowerJan 10–Jan 24
LeeksJan 10–Jan 24
Swiss chardJan 10–Feb 7
ParsleyJan 10–Jan 31
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesDec 27–Jan 10
AsparagusDec 27–Jan 10

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FDec 21Jan 24Mar 5Nov 27Dec 15Jan 26
Hard freeze, 28°FDec 5Dec 31Feb 1Dec 1Dec 26Jan 25

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 Woodland Hills Pierce College (USC00049785) sits 11.6 miles from the center of Simi Valley at 790 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 Simi Valley, CA?

The average last frost date in Simi Valley is January 24, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 5.

When is the first frost in Simi Valley?

The first frost in fall usually comes around December 15. One year in ten it arrives before November 27.

How long is the growing season in Simi Valley?

About 329 days between the average last and first frost.

When should I plant tomatoes in Simi Valley?

Plant tomato seedlings outside from February 15 to March 1. Start seeds indoors six to eight weeks earlier.

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