December weather forecast
Atascadero, CA

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The Sunken Gardens Park overlooking the Atascadero City Hall in California
The Sunken Gardens Park overlooking the Atascadero City Hall in California

Weather in December

December, the first month of the winter in Atascadero, is still a refreshing month, with temperature in the range of an average low of 42.8°F (6°C) and an average high of 58.5°F (14.7°C).

Temperature

During the coldest month, December, temperatures average a high of 58.5°F (14.7°C) and a low of 42.8°F (6°C).

Humidity

The average relative humidity in December is 65%.

Rainfall

In December, the rain falls for 7.6 days. Throughout December, 1.38" (35mm) of precipitation is accumulated. In Atascadero, during the entire year, the rain falls for 54.8 days and collects up to 8.66" (220mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 48min of daylight.
On the first day of December in Atascadero, sunrise is at 6:54 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 5:00 pm PST.

Sunshine

The months with the least sunshine are February and December, with an average of 6.3h of sunshine.

UV index

The months with the lowest UV index in Atascadero are February, November and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum daily UV index of 3 during December translates into the following directions:
Undertake precautions - Guarding against sun damage is counselled. Around midday, solar radiation is most harmful; hence, exposure should be limited. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Updated: Jun 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

The coldest period is December, when temperatures fluctuate between an average high of 58.5°F (14.7°C) and a low of 42.8°F (6°C).

What is the average December temperature?

The high-temperature, in December, in Atascadero, is 58.5°F (14.7°C), while the low-temperature averages to 42.8°F (6°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in September is evaluated at 84.2°F (29°C).

What is the average humidity in December?

In December, the average relative humidity is 65%.

How many days does it rain in December in Atascadero?

In Atascadero, in December, during 7.6 rainfall days, 1.38" (35mm) of precipitation is typically accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 48min of daylight.

How many hours of daylight does Atascadero have in December?

In December, the average day length is 9h and 49min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:54 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 5:00 pm PST.

What is the month with the least sunshine?

February and December, with an average of 6.3h of sunshine, are months with the least sunshine.

How long on average sun shines in December?

The average sunshine duration in December is 6.3h.

What are the months with the lowest UV index?

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

What is the UV index intensity in December?

In Atascadero, the average daily maximum UV index in December 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
Atascadero, CA

Average temperature in December - Atascadero, CA
  • Average high temperature in December: 58.5°F

The warmest month (with the highest average high temperature) is August (85.5°F).
The month with the lowest average high temperature is December (58.5°F).

  • Average low temperature in December: 42.8°F

The month with the highest average low temperature is September (59.9°F).
The coldest month (with the lowest average low temperature) is December (42.8°F).

Average pressure in December
Atascadero, CA

Average pressure in December - Atascadero, CA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).

Average wind speed in December
Atascadero, CA

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

The windiest months (with the highest average wind speed) are March and April (5.9mph).
The calmest months (with the lowest average wind speed) are August and September (4.5mph).

Average humidity in December
Atascadero, CA

Average humidity in December - Atascadero, CA
  • Average humidity in December: 65%

The months with the highest relative humidity are February and March (68%).
The month with the lowest relative humidity is September (50%).

Average rainfall in December
Atascadero, CA

Average rainfall in December - Atascadero, CA
  • Average rainfall in December: 1.38"

The wettest month (with the highest rainfall) is March (1.73").
The driest months (with the least rainfall) are June and August (0.04").

Average rainfall days in December
Atascadero, CA

Average rainfall days in December - Atascadero, CA
  • Average rainfall days in December: 7.6 days

The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is June (0.8 days).

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

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

The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).

  • Average sunshine in December: 6h and 2min

The months with the most sunshine are June and July (Average sunshine: 12h and 0min).
The months with the least sunshine are February and December (Average sunshine: 6h and 18min).

Average sunshine days in December
Atascadero, CA

Average sunshine days in December - Atascadero, CA
  • Average sunshine days in December: 22 days

The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is February (19.7 days).

Average UV index in December
Atascadero, CA

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

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

Average cloud cover in December
Atascadero, CA

Average cloud cover in December - Atascadero, CA
  • Average cloud cover in December: 29

The month with the most cloud cover is March (Cloud cover 31).
The month with the least cloud cover is August (Cloud cover 6).

Average visibility in December
Atascadero, CA

Average visibility in December - Atascadero, 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).

Atascadero, California, USA

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