December weather forecast
Cupertino, CA

Weather in December

The first month of the winter, December, is also a moderate month in Cupertino, California, with an average temperature fluctuating between 44.4°F (6.9°C) and 57°F (13.9°C).

Temperature

December is the coldest month, with an average high-temperature of 57°F (13.9°C) and an average low-temperature of 44.4°F (6.9°C).

Humidity

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

Rainfall

In Cupertino, in December, it is raining for 8.2 days, with typically 0.87" (22mm) of accumulated precipitation. In Cupertino, California, during the entire year, the rain falls for 53.6 days and collects up to 5.39" (137mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 38min of daylight.
On the first day of December in Cupertino, sunrise is at 7:03 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 5:00 pm PST.

Sunshine

The month with the least sunshine in Cupertino is December, with an average of 5.9h of sunshine.

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 estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: The daily maximum UV index of 3 in December interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the coldest month in Cupertino?

December is the coldest month in Cupertino, with an average high-temperature of 57°F (13.9°C) and an average low-temperature of 44.4°F (6.9°C).

What is the average humidity in December in Cupertino?

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

How many days does it rain in December in Cupertino?

In Cupertino, in December, during 8.2 rainfall days, 0.87" (22mm) of precipitation is typically accumulated.

What is the month with the shortest days in Cupertino?

The month with the shortest days in Cupertino is December, with an average of 9h and 38min of daylight.

How many hours of daylight does Cupertino have in December?

In December, the average day length is 9h and 38min.

When are sunrise and sunset in December in Cupertino?

On the first day of December, sunrise is at 7:03 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 5:00 pm PST.

What is the month with the least sunshine in Cupertino?

December has the least sunshine of the year in Cupertino, California, with an average of 5.9h of sunshine.

How long on average sun shines in December in Cupertino?

The average sunshine duration in December is 5.9h.

When is the lowest UV index in Cupertino?

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

What is the UV index intensity in December in Cupertino?

In Cupertino, California, the average daily maximum UV index in December is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.

Average temperature in December
Cupertino, CA

Average temperature in December - Cupertino, CA
  • Average high temperature in December: 57°F

The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is December (57°F).

  • Average low temperature in December: 44.4°F

The month with the highest average low temperature is August (56.1°F).
The coldest months (with the lowest average low temperature) are February and March (44.2°F).

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Average pressure in December
Cupertino, CA

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

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).

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Average wind speed in December
Cupertino, CA

Average wind speed in December - Cupertino, CA
  • Average wind speed in December: 5.3mph

The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest month (with the lowest average wind speed) is September (4.6mph).

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Average humidity in December
Cupertino, CA

Average humidity in December - Cupertino, 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, September and October (64%).

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Average rainfall in December
Cupertino, CA

Average rainfall in December - Cupertino, CA
  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is February (1.02").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in December
Cupertino, CA

Average rainfall days in December - Cupertino, CA
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is March (9 days).
The month with the least rainy days is August (0.8 days).

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

Average daylight in December / Average sunshine in December - Cupertino, CA
  • Average daylight in December: 9h and 38min

The month with the longest days is June (Average daylight: 14h and 41min).
The month with the shortest days is December (Average daylight: 9h and 38min).

  • Average sunshine in December: 5.9h

The months with the most sunshine are July and August (Average sunshine: 12h).
The month with the least sunshine is December (Average sunshine: 5.9h).

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Average sunshine days in December
Cupertino, CA

Average sunshine days in December - Cupertino, CA
  • Average sunshine days in December: 21.5 days

The month with the most sunshine days is August (28.5 days).
The months with the least sunshine days are February and March (20.8 days).

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Average UV index in December
Cupertino, CA

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

The month with the highest UV index is June (UV index 6).
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
Cupertino, CA

Average cloud cover in December - Cupertino, CA
  • Average cloud cover in December: 33

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 7).

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Average visibility in December
Cupertino, CA

Average visibility in December - Cupertino, 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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