December weather forecast
Cupertino, CA

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Weather in December

The first month of the winter, December, is still a refreshing month in Cupertino, California, with temperature in the range of an average low of 44.4°F (6.9°C) and an average high of 57°F (13.9°C).

Temperature

Cupertino's coldest month, December, registers temperatures that range from a high of 57°F (13.9°C) to a low of 44.4°F (6.9°C).

Humidity

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

Rainfall

In Cupertino, California, in December, during 8.2 rainfall days, 0.87" (22mm) of precipitation is typically accumulated. Throughout the year, there are 53.6 rainfall days, and 5.39" (137mm) of precipitation is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 36min of daylight.
On the first day of December, sunrise is at 7:04 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 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 of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 3 suggests this advice:
Ensure safety - Sun damage prevention is strongly urged. When the Sun is at its strongest around midday, find shade and limit exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Updated: Aug 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

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

What is the usual temperature for Cupertino in December?

In December, in Cupertino, the average high-temperature is 57°F (13.9°C), and the average low-temperature is 44.4°F (6.9°C).

What is the average humidity in December in Cupertino?

The average relative humidity in December is 71%.

How much does it rain in December?

In Cupertino, California, in December, it is raining for 8.2 days, with typically 0.87" (22mm) of accumulated precipitation.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 36min of daylight.

What is the average length of the day in December?

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

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 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?

With an average of 5.9h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December?

In December, the average sunshine duration is 5.9h.

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 in Cupertino, California.

How high is the UV index in December?

In December, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a moderate health threat 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
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).

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).

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).

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%).

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").

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).

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 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: 5h and 5min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

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).

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).

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).

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).

Cupertino, California, USA

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