December weather forecast
Placentia, CA

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Weather in December

December, the first month of the winter in Placentia, is still a comfortable month, with an average temperature fluctuating between 50.2°F (10.1°C) and 64.2°F (17.9°C).

Temperature

With average high and low temperatures of 64.2°F (17.9°C) and 50.2°F (10.1°C) respectively, December is Placentia's coldest month.

Humidity

In December, the average relative humidity in Placentia is 54%.

Rainfall

The month with the most rainfall is December, when the rain falls for 6.8 days and typically aggregates up to 1.65" (42mm) of precipitation.

Daylight

December has the shortest days of the year, with an average of 9h and 54min of daylight.
On the first day of the month, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of December, sunrise is at 6:56 am and sunset at 4:53 pm PST.

Sunshine

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

UV index

January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: A daily maximum UV index of 4 in December translates into the following instructions:
Guard yourself - Avoiding sunburn is suggested. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Updated: Aug 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

December, known for its average high temperature of 64.2°F (17.9°C) and an average low temperature of 50.2°F (10.1°C), is the coldest month.

What is the usual temperature for Placentia in December?

The average high-temperature and low-temperature during December are 64.2°F (17.9°C) and 50.2°F (10.1°C) respectively. The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in September is estimated at 86°F (30°C).

What is the average humidity in December?

The average relative humidity in December is 54%.

What is the rainiest month?

The month with the most rainfall is December, when the rain falls for 6.8 days and typically aggregates up to 1.65" (42mm) of precipitation.

How many days does it rain in December?

In Placentia, in December, during 6.8 rainfall days, 1.65" (42mm) of precipitation is typically accumulated.

What is the month with the shortest days?

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

How many hours of daylight does Placentia have in December?

In December, the average day length is 9h and 56min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:53 pm PST.

What are the months with the least sunshine?

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

How long on average sun shines in December?

The average sunshine duration in December is 6.8h.

What are the months with the lowest UV index?

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

What is the UV index reading in December?

The average daily maximum UV index in December is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health 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
Placentia, CA

Average temperature in December - Placentia, CA
  • Average high temperature in December: 64.2°F

The warmest month (with the highest average high temperature) is August (85.3°F).
The month with the lowest average high temperature is December (64.2°F).

  • Average low temperature in December: 50.2°F

The month with the highest average low temperature is August (65.7°F).
The coldest month (with the lowest average low temperature) is February (49.6°F).

Average pressure in December
Placentia, CA

Average pressure in December - Placentia, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in December
Placentia, CA

Average wind speed in December - Placentia, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).

Average humidity in December
Placentia, CA

Average humidity in December - Placentia, CA
  • Average humidity in December: 54%

The month with the highest relative humidity is June (63%).
The month with the lowest relative humidity is November (50%).

Average rainfall in December
Placentia, CA

Average rainfall in December - Placentia, CA
  • Average rainfall in December: 1.65"

The wettest month (with the highest rainfall) is December (1.65").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in December
Placentia, CA

Average rainfall days in December - Placentia, CA
  • Average rainfall days in December: 6.8 days

The month with the highest number of rainy days is March (7.4 days).
The month with the least rainy days is June (1.4 days).

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

Average daylight in December / Average sunshine in December - Placentia, 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 month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 48min).

Average sunshine days in December
Placentia, CA

Average sunshine days in December - Placentia, CA
  • Average sunshine days in December: 23.4 days

The month with the most sunshine days is August (26.7 days).
The month with the least sunshine days is February (20.7 days).

Average UV index in December
Placentia, CA

Average UV index in December - Placentia, 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
Placentia, CA

Average cloud cover in December - Placentia, CA
  • Average cloud cover in December: 22

The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in December
Placentia, CA

Average visibility in December - Placentia, 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).

Placentia, California, USA

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