December weather forecast
Riverdale Park, CA

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Weather in December

December, the first month of the winter in Riverdale Park, is still a mild month, with an average temperature fluctuating between 55.6°F (13.1°C) and 41.9°F (5.5°C).

Temperature

December tends to be the coldest month, with temperatures averaging a daily high of 55.6°F (13.1°C) and a low of 41.9°F (5.5°C).

Humidity

In December, the average relative humidity in Riverdale Park is 70%.

Rainfall

In December, the rain falls for 8.2 days. Throughout December, 1.22" (31mm) of precipitation is accumulated. In Riverdale Park, during the entire year, the rain falls for 54.3 days and collects up to 6.54" (166mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 36min of daylight.
On the first day of December in Riverdale Park, sunrise is at 7:01 am and sunset at 4:45 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:56 pm PST.

Sunshine

The month with the least sunshine in Riverdale Park is December, with an average of 6h of sunshine.

UV index

The months with the lowest UV index in Riverdale Park are January, February, November and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 3 in December transforms into the following instructions:
Undertake precautions - Guarding against sun damage is counselled. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. During bright days, sunglasses that offer UVA and UVB defense are recommended.
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Frequently asked questions

What part of the year is the coldest in Riverdale Park?

In Riverdale Park, December registers the lowest temperatures, averaging 55.6°F (13.1°C) at the peak and 41.9°F (5.5°C) at the lowest.

What is the usual temperature for Riverdale Park in December?

The high-temperature, in December, in Riverdale Park, records 55.6°F (13.1°C), while the low-temperature is 41.9°F (5.5°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines relative humidity and air temperature, in September is calculated to be 93.2°F (34°C).

What is the average humidity in December in Riverdale Park?

The average relative humidity in December in Riverdale Park, California, is 70%.

How much does it rain in Riverdale Park in December?

In December, the rain falls for 8.2 days. Throughout December, 1.22" (31mm) of precipitation is accumulated.

What is the month with the shortest days in Riverdale Park?

The month with the shortest days in Riverdale Park is December, with an average of 9h and 36min of daylight.

What is the average length of the day in December in Riverdale Park?

In Riverdale Park, the average day length in December is 9h and 37min.

What time are sunrise and sunset in December in Riverdale Park?

In December, on the first day of the month, sunrise is at 7:01 am and sunset at 4:45 pm. On the last day of the month, in Riverdale Park, California, sunrise is at 7:18 am and sunset at 4:56 pm PST.

What is the month with the least sunshine in Riverdale Park?

December has the least sunshine of the year, with an average of 6h of sunshine.

How many hours of sunshine does Riverdale Park have in December?

The average sunshine duration in December in Riverdale Park, California, is 6h.

What are the months with the lowest UV index in Riverdale Park?

January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.

What is the UV index intensity in December in Riverdale Park?

In December, the average daily maximum UV index in Riverdale Park, California, is 3. A UV Index estimate of 3 to 5 represents a medium hazard to health from 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
Riverdale Park, CA

Average temperature in December - Riverdale Park, CA
  • Average high temperature in December: 55.6°F

The warmest month (with the highest average high temperature) is July (97.7°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in December: 41.9°F

The month with the highest average low temperature is July (62.1°F).
The coldest months (with the lowest average low temperature) are January and December (41.9°F).

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Average pressure in December
Riverdale Park, CA

Average pressure in December - Riverdale Park, CA
  • Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in December
Riverdale Park, CA

Average wind speed in December - Riverdale Park, CA
  • Average wind speed in December: 5.7mph

The windiest month (with the highest average wind speed) is June (7.3mph).
The calmest month (with the lowest average wind speed) is November (5.2mph).

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Average humidity in December
Riverdale Park, CA

Average humidity in December - Riverdale Park, CA
  • Average humidity in December: 70%

The month with the highest relative humidity is January (72%).
The month with the lowest relative humidity is July (37%).

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Average rainfall in December
Riverdale Park, CA

Average rainfall in December - Riverdale Park, CA
  • Average rainfall in December: 1.22"

The wettest month (with the highest rainfall) is March (1.3").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in December
Riverdale Park, CA

Average rainfall days in December - Riverdale Park, CA
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).

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Average daylight in December /
Average sunshine in December
Riverdale Park, CA

Average daylight in December / Average sunshine in December - Riverdale Park, CA
  • Average daylight in December: 9h and 4min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in December: 6h and 0min

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 0min).

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Average sunshine days in December
Riverdale Park, CA

Average sunshine days in December - Riverdale Park, CA
  • Average sunshine days in December: 22 days

The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (19.6 days).

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Average UV index in December
Riverdale Park, CA

Average UV index in December - Riverdale Park, CA
  • Average UV index in December: 3

The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in December
Riverdale Park, CA

Average cloud cover in December - Riverdale Park, CA
  • Average cloud cover in December: 32

The month with the most cloud cover is March (Cloud cover 33).
The month with the least cloud cover is July (Cloud cover 4).

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Average visibility in December
Riverdale Park, CA

Average visibility in December - Riverdale Park, 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).

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Riverdale Park, California, USA

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