December weather forecast
Pleasanton, CA

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Neon-lit buildings in the CBD of downtown Pleasanton, California
Neon-lit buildings in the CBD of downtown Pleasanton, California

Weather in December

December, the first month of the winter in Pleasanton, is also a fresh month, with an average temperature varying between 55°F (12.8°C) and 41.7°F (5.4°C).

Temperature

With average high and low temperatures of 55°F (12.8°C) and 41.7°F (5.4°C) respectively, December is Pleasanton's coldest month.

Humidity

In Pleasanton, the average relative humidity in December is 71%.

Rainfall

In December, the rain falls for 10.4 days. Throughout December, 1.81" (46mm) of precipitation is accumulated. In Pleasanton, during the entire year, the rain falls for 70.2 days and collects up to 10.98" (279mm) of precipitation.

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:04 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:59 pm PST.

Sunshine

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

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.
Note: In December, the maximum UV index of 3 suggests this advice:
Ensure safety - Imperative it is to shield skin and eyes from damage. To guard against the harmful effects of the Sun, minimize exposure during midday. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim.
Updated: Aug 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

December is the coldest month, with an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C).

What is the temperature in December?

In Pleasanton, in December, the average high-temperature is 55°F (12.8°C), and the average low-temperature is 41.7°F (5.4°C). In September, the average heat index (a.k.a. 'feels like', 'real feel'), which factors the actual air temperature with the relative humidity, is evaluated at 84.2°F (29°C).

What is the average humidity in December?

The average relative humidity in December is 71%.

How many days does it rain in December?

In Pleasanton, during December, the rain falls for 10.4 days and regularly aggregates up to 1.81" (46mm) of precipitation.

What is the month with the shortest days?

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

What is the average length of the day in December?

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

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:59 pm PST.

What is the month with the least sunshine?

With an average of 6h 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 6h.

What are the months with the lowest UV index?

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 Pleasanton?

In Pleasanton, the average daily maximum UV index in December is 3. A UV Index estimate of 3 to 5 represents 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
Pleasanton, CA

Average temperature in December - Pleasanton, CA
  • Average high temperature in December: 55°F

The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in December: 41.7°F

The month with the highest average low temperature is August (56.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).

Average pressure in December
Pleasanton, CA

Average pressure in December - Pleasanton, CA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

Average wind speed in December
Pleasanton, CA

Average wind speed in December - Pleasanton, CA
  • Average wind speed in December: 4.7mph

The windiest month (with the highest average wind speed) is May (6.3mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).

Average humidity in December
Pleasanton, CA

Average humidity in December - Pleasanton, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are July and September (56%).

Average rainfall in December
Pleasanton, CA

Average rainfall in December - Pleasanton, CA
  • Average rainfall in December: 1.81"

The wettest month (with the highest rainfall) is February (2.05").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Pleasanton, CA

Average rainfall days in December - Pleasanton, CA
  • Average rainfall days in December: 10.4 days

The month with the highest number of rainy days is March (12.4 days).
The month with the least rainy days is August (0.9 days).

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

Average daylight in December / Average sunshine in December - Pleasanton, 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).

Average sunshine days in December
Pleasanton, CA

Average sunshine days in December - Pleasanton, CA
  • Average sunshine days in December: 19.6 days

The month with the most sunshine days is August (29 days).
The month with the least sunshine days is March (17.6 days).

Average UV index in December
Pleasanton, CA

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

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

Average cloud cover in December
Pleasanton, CA

Average cloud cover in December - Pleasanton, CA
  • Average cloud cover in December: 34

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).

Average visibility in December
Pleasanton, CA

Average visibility in December - Pleasanton, 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).

Pleasanton, California, USA

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