December weather forecast
Sylmar, CA

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Weather in December

The first month of the winter, December, is still a refreshing month in Sylmar, California, with temperature in the range of an average low of 46.2°F (7.9°C) and an average high of 61.7°F (16.5°C).

Temperature

December, with its average high-temperature of 61.7°F (16.5°C) and an average low-temperature of 46.2°F (7.9°C), holds the record as the coldest month.

Humidity

In December, the average relative humidity is 52%.

Rainfall

In Sylmar, during December, the rain falls for 5 days and regularly aggregates up to 1.42" (36mm) of precipitation. In Sylmar, during the entire year, the rain falls for 39.8 days and collects up to 7.52" (191mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 54min of daylight.
On the first day of December, sunrise is at 6:42 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 4:54 pm PST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 6.8h of sunshine.

UV index

The month with the lowest UV index is December, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the average person.
Note: In December, a daily maximum UV index of 3 leads to the following instructions:
Be vigilant - Suggestions to stave off sun damage are provided. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
Updated: Aug 15, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest?

In Sylmar, California, the average lowest temperatures are observed in December, with a high of 61.7°F (16.5°C) and a low of 46.2°F (7.9°C).

What is the usual temperature for Sylmar in December?

December temperatures vary between a high-temperature of 61.7°F (16.5°C) and a low-temperature of 46.2°F (7.9°C). In September, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, is computed to be 84.2°F (29°C).

What is the average humidity in December?

The average relative humidity in December is 52%.

How many days does it rain in December in Sylmar?

In December, the rain falls for 5 days. Throughout December, 1.42" (36mm) of precipitation is accumulated.

What is the month with the shortest days?

With an average of 9h and 54min of daylight, December has the shortest days of the year.

How many hours of daylight does Sylmar have in December?

In December, the average day length is 9h and 55min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:42 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 4:54 pm PST.

What are the months with the least sunshine?

January, February and December, with an average of 6.8h of sunshine, are months with the least sunshine.

How long on average sun shines in December in Sylmar?

In December, the average sunshine duration is 6.8h.

When is the lowest UV index?

With an average maximum UV index of 3, December is the month with the lowest UV index.

How high is the UV index in December in Sylmar?

In Sylmar, California, the average daily maximum UV index in December is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Sylmar, CA

Average temperature in December - Sylmar, CA
  • Average high temperature in December: 61.7°F

The warmest month (with the highest average high temperature) is August (85.8°F).
The month with the lowest average high temperature is December (61.7°F).

  • Average low temperature in December: 46.2°F

The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is December (46.2°F).

Average pressure in December
Sylmar, CA

Average pressure in December - Sylmar, CA
  • Average pressure in December: 30.08"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in December
Sylmar, CA

Average wind speed in December - Sylmar, CA
  • Average wind speed in December: 6.2mph

The windiest months (with the highest average wind speed) are January and December (6.2mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).

Average humidity in December
Sylmar, CA

Average humidity in December - Sylmar, CA
  • Average humidity in December: 52%

The month with the highest relative humidity is June (58%).
The month with the lowest relative humidity is November (47%).

Average rainfall in December
Sylmar, CA

Average rainfall in December - Sylmar, CA
  • Average rainfall in December: 1.42"

The wettest month (with the highest rainfall) is February (1.54").
The driest month (with the least rainfall) is June (0").

Average rainfall days in December
Sylmar, CA

Average rainfall days in December - Sylmar, CA
  • Average rainfall days in December: 5 days

The month with the highest number of rainy days is March (6.3 days).
The month with the least rainy days is June (0.8 days).

Average daylight in December /
Average sunshine in December
Sylmar, CA

Average daylight in December / Average sunshine in December - Sylmar, CA
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 6h and 5min

The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 48min).

Average sunshine days in December
Sylmar, CA

Average sunshine days in December - Sylmar, CA
  • Average sunshine days in December: 25.2 days

The month with the most sunshine days is May (28.8 days).
The month with the least sunshine days is February (22.9 days).

Average UV index in December
Sylmar, CA

Average UV index in December - Sylmar, CA
  • Average UV index in December: 3

The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in December
Sylmar, CA

Average cloud cover in December - Sylmar, CA
  • Average cloud cover in December: 21

The month with the most cloud cover is March (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 4).

Average visibility in December
Sylmar, CA

Average visibility in December - Sylmar, CA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Sylmar, California, USA

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