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December weather forecast in Simi Valley

30 days Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

30 days Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Sun

Sunday

Mon

Monday

Tue

Tuesday

Wed

Wednesday

Thu

Thursday

Fri

Friday

Sat

Saturday

30 November, sun

	705 mmHg		54%
	2.9 m/s		+17

30 November, Sunday. day, 16°; night, 5°; rain

1 December, mon

	705 mmHg		57%
	3.1 m/s		+17

1 December, Monday. day, 16°; night, 5°; clear

2 December, tue

	705 mmHg		56%
	3 m/s		+17

2 December, Tuesday. day, 16°; night, 5°; clear

3 December, wed

	706 mmHg		54%
	3.2 m/s		+17

3 December, Wednesday. day, 16°; night, 6°; clear

4 December, thu

	706 mmHg		51%
	3.3 m/s		+17

4 December, Thursday. day, 16°; night, 5°; clear

5 December, fri

	706 mmHg		51%
	3.1 m/s		+17

5 December, Friday. day, 16°; night, 5°; partly cloudy

6 December, sat

	705 mmHg		56%
	3.1 m/s		+17

6 December, Saturday. day, 16°; night, 5°; rain

7 December, sun

	705 mmHg		62%
	3.3 m/s		+17

7 December, Sunday. day, 15°; night, 6°; rain

8 December, mon

	706 mmHg		58%
	3 m/s		+16

8 December, Monday. day, 15°; night, 5°; clear

9 December, tue

	706 mmHg		57%
	3.6 m/s		+17

9 December, Tuesday. day, 15°; night, 5°; partly cloudy

10 December, wed

	706 mmHg		54%
	3.3 m/s		+17

10 December, Wednesday. day, 15°; night, 5°; clear

11 December, thu

	706 mmHg		57%
	3.5 m/s		+17

11 December, Thursday. day, 15°; night, 5°; overcast

12 December, fri

	705 mmHg		58%
	3.2 m/s		+17

12 December, Friday. day, 15°; night, 5°; clear

13 December, sat

	706 mmHg		63%
	2.9 m/s		+16

13 December, Saturday. day, 15°; night, 4°; clear

14 December, sun

	706 mmHg		63%
	3.5 m/s		+16

14 December, Sunday. day, 15°; night, 4°; partly cloudy

15 December, mon

	706 mmHg		58%
	3.5 m/s		+16

15 December, Monday. day, 14°; night, 4°; partly cloudy

16 December, tue

	706 mmHg		57%
	3.7 m/s		+16

16 December, Tuesday. day, 15°; night, 4°; clear

17 December, wed

	705 mmHg		55%
	3.7 m/s		+16

17 December, Wednesday. day, 15°; night, 5°; rain

18 December, thu

	706 mmHg		56%
	3.4 m/s		+16

18 December, Thursday. day, 15°; night, 5°; clear

19 December, fri

	706 mmHg		56%
	3.3 m/s		+16

19 December, Friday. day, 15°; night, 4°; clear

20 December, sat

	706 mmHg		58%
	2.9 m/s		+16

20 December, Saturday. day, 15°; night, 4°; partly cloudy

21 December, sun

	705 mmHg		58%
	2.9 m/s		+16

21 December, Sunday. day, 14°; night, 4°; overcast

22 December, mon

	704 mmHg		60%
	3.5 m/s		+16

22 December, Monday. day, 14°; night, 4°; rain

23 December, tue

	706 mmHg		62%
	3.5 m/s		+16

23 December, Tuesday. day, 14°; night, 4°; overcast

24 December, wed

	706 mmHg		60%
	3.3 m/s		+16

24 December, Wednesday. day, 14°; night, 4°; clear

25 December, thu

	706 mmHg		56%
	3.7 m/s		+15

25 December, Thursday. day, 14°; night, 4°; clear

26 December, fri

	706 mmHg		55%
	3.2 m/s		+15

26 December, Friday. day, 14°; night, 3°; partly cloudy

27 December, sat

	706 mmHg		55%
	3.2 m/s		+15

27 December, Saturday. day, 14°; night, 3°; clear

28 December, sun

	706 mmHg		58%
	3.1 m/s		+15

28 December, Sunday. day, 14°; night, 3°; clear

29 December, mon

	705 mmHg		60%
	2.9 m/s		+15

29 December, Monday. day, 15°; night, 4°; rain

30 December, tue

	705 mmHg		61%
	3 m/s		+16

30 December, Tuesday. day, 14°; night, 4°; rain

31 December, wed

	704 mmHg		64%
	3.3 m/s		+16

31 December, Wednesday. day, 14°; night, 4°; overcast

1 January, thu

	705 mmHg		58%
	3.6 m/s		+15

1 January, Thursday. day, 14°; night, 4°; clear

2 January, fri

	706 mmHg		55%
	3.4 m/s		+15

2 January, Friday. day, 14°; night, 4°; partly cloudy

3 January, sat

	706 mmHg		58%
	3.1 m/s		+15

3 January, Saturday. day, 14°; night, 5°; rain

Average data for 10 years

Simi Valley December

15

sunny days

6

days with precipitation

6

cloudy days

15 sunny days; 6 days with precipitation; 6 cloudy days;

58

%

air humidity

2

m/s

WindS

62

mm of precipitation

(16% of annual average)

+16

°C

Water temperature

air humidity 58%; 62 millimeters of precipitation (16% of annual average); Wind southerly 2 Meters per second; Water temperature +16°

Weather graphs for December

TemperatureWater temperaturePrecipitation chance, %Humidity, %Wind, m/sPressure, mmHg

S

S

S

S

SE

S

S

S

S

S

S

SW

SW

SW

S

S

S

S

S

S

S

S

S

S

SE

S

S

S

S

SW

SW

1

Average data for 10 years

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

Daytime temperature

Night-time temperature

Cities near you

Los Angeles
San Diego
Santa Monica
Beverly Hills
Monterey
Mexicali
Santa Barbara
Glendale
San Luis Obispo

Cities with similar weather in December

Tunis
Belek
Marmaris
Lisbon
Aqaba
Eylat
Sousse
Baghdad
Hammamet

The weather forecast for December 2025 is based on historical data from the past 10 years.

December in Simi Valley is the coldest month of the year. In December, the weather in Simi Valley is typically warm. Average daily high temperature in December is about 15 degrees above zero. On average, Simi Valley has 15 sunny, 6 rainy, 6 partly cloudy, and 4 cloudy days in December. The rains are usually moderate. December as well as January and February is considered the most uncomfortable time to visit Simi Valley.

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