December weather forecast
El Cajon, CA

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Weather in December

Finally, December brings with it the chill of the winter season, covering El Cajon in a cool atmosphere. As temperatures continue to fall, the climate becomes conducive for cozy indoor activities. With the year almost ending, long nights and condensed daylight hours dominate most part of the day. The weather during this month tends to be colder than October and November, heralding the arrival of a new year with a fresh and cool end. The average temperature ranges from 63.7°F (17.6°C) to 47.8°F (8.8°C) coupled with increased precipitation of 1.42" (36mm), emphasizes the city's transition into the grip of winter.

Temperature

December, on average, is the coldest month, registering a high temperature of 63.7°F (17.6°C) and a low of 47.8°F (8.8°C).

Humidity

In December, the average relative humidity is 59%.

Rainfall

In December, the rain falls for 5.9 days. Throughout December, 1.42" (36mm) of precipitation is accumulated. Throughout the year, there are 56.1 rainfall days, and 8.27" (210mm) of precipitation is accumulated.

Daylight

The month with the shortest days is December, with an average of 10h and 0min of daylight.
On the first day of the month, sunrise is at 6:32 am and sunset at 4:41 pm. On the last day of December, sunrise is at 6:50 am and sunset at 4:52 pm PST.

Sunshine

The month with the least sunshine is December, with an average of 6.7h of sunshine.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: In December, the maximum UV index of 4 translates into these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. The solar radiation around mid-day is intense; avoid the Sun and stay safe. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.

Frequently asked questions

What month is the coldest in El Cajon?

December stands out as El Cajon's coldest month, with an average high-temperature of 63.7°F (17.6°C) and a low-temperature of 47.8°F (8.8°C).

What is the temperature in December?

The high-temperature, in December, in El Cajon, records 63.7°F (17.6°C), while the low-temperature is 47.8°F (8.8°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in September is computed to be 84.2°F (29°C).

What is the average humidity in December?

In El Cajon, the average relative humidity in December is 59%.

How much does it rain in December?

In December, the rain falls for 5.9 days. Throughout December, 1.42" (36mm) of precipitation is accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 10h and 0min of daylight.

How many hours of daylight does El Cajon have in December?

In El Cajon, the average day length in December is 10h and 2min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:32 am and sunset at 4:41 pm. On the last day of the month, in El Cajon, sunrise is at 6:50 am and sunset at 4:52 pm PST.

What is the month with the least sunshine?

With an average of 6.7h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December?

The average sunshine duration in December is 6.7h.

When is the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 4.

How high is the UV index in December?

In El Cajon, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a moderate health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
El Cajon, CA

Average temperature in December - El Cajon, CA
  • Average high temperature in December: 63.7°F

The warmest month (with the highest average high temperature) is August (83.8°F).
The month with the lowest average high temperature is December (63.7°F).

  • Average low temperature in December: 47.8°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (47.8°F).

Average pressure in December
El Cajon, CA

Average pressure in December - El Cajon, CA
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are June and September (29.87"Hg).

Average wind speed in December
El Cajon, CA

Average wind speed in December - El Cajon, CA
  • Average wind speed in December: 4.8mph

The windiest month (with the highest average wind speed) is April (5.5mph).
The calmest month (with the lowest average wind speed) is October (4.3mph).

Average humidity in December
El Cajon, CA

Average humidity in December - El Cajon, CA
  • Average humidity in December: 59%

The month with the highest relative humidity is May (66%).
The month with the lowest relative humidity is November (53%).

Average rainfall in December
El Cajon, CA

Average rainfall in December - El Cajon, CA
  • Average rainfall in December: 1.42"

The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in December
El Cajon, CA

Average rainfall days in December - El Cajon, CA
  • Average rainfall days in December: 5.9 days

The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1.4 days).

Average daylight in December /
Average sunshine in December
El Cajon, CA

Average daylight in December / Average sunshine in December - El Cajon, CA
  • Average daylight in December: 10h and 0min

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in December: 6h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).

Average sunshine days in December
El Cajon, CA

Average sunshine days in December - El Cajon, CA
  • Average sunshine days in December: 24.7 days

The month with the most sunshine days is June (27.7 days).
The month with the least sunshine days is February (21.9 days).

Average UV index in December
El Cajon, CA

Average UV index in December - El Cajon, CA
  • Average UV index in December: 4

The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 4).

Average cloud cover in December
El Cajon, CA

Average cloud cover in December - El Cajon, CA
  • Average cloud cover in December: 23

The months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 7).

Average visibility in December
El Cajon, CA

Average visibility in December - El Cajon, 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).

El Cajon, California, USA

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