December weather forecast
Mountain View, CA

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A street in Mountain View Town, California, with neon-lit building, trees, and parked cars
A street in Mountain View Town, California, with neon-lit building, trees, and parked cars

Weather in December

The first month of the winter, December, is also a moderate month in Mountain View, California, with an average temperature varying between 44.1°F (6.7°C) and 56.5°F (13.6°C).

Temperature

In Mountain View, the lowest average temperatures are observed in December, with a high of 56.5°F (13.6°C) and a low of 44.1°F (6.7°C).

Humidity

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

Rainfall

The wettest months are February, March and December, with an average 0.83" (21mm) of rainfall.

Daylight

The month with the shortest days is December, with an average of 9h and 36min of daylight.
On the first day of the month, sunrise is at 7:04 am and sunset at 4:50 pm. On the last day of December, in Mountain View, sunrise is at 7:22 am and sunset at 5:00 pm PST.

Sunshine

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

UV index

The months with the lowest UV index are 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 unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The UV index of 3 during December leads to these advisories:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Updated: Jun 19, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the coldest?

Mountain View's coldest month, December, registers temperatures that range from a high of 56.5°F (13.6°C) to a low of 44.1°F (6.7°C).

What are December temperatures?

The high-temperature, in December, in Mountain View, is 56.5°F (13.6°C), while the low-temperature averages to 44.1°F (6.7°C).

What is the average humidity in December?

The average relative humidity in December is 71%.

What is the wettest month?

The wettest months are February, March and December, with an average 0.83" (21mm) of rainfall.

How much does it rain in Mountain View in December?

In Mountain View, in December, it is raining for 8.2 days, with typically 0.83" (21mm) of accumulated precipitation.

What is the month with the shortest days?

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

What is the average length of the day in December?

The average day length in December is 9h and 38min.

When 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 many hours of sunshine does Mountain View have in December?

In December, the average sunshine duration in Mountain View is 5.9h.

What is the month with the lowest UV index in Mountain View?

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

How high is the UV index in December?

In Mountain View, the average daily maximum UV index in December is 3. A UV Index estimate of 3 to 5 represents a moderate vulnerability 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
Mountain View, CA

Average temperature in December - Mountain View, CA
  • Average high temperature in December: 56.5°F

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (56.5°F).

  • Average low temperature in December: 44.1°F

The month with the highest average low temperature is August (56.8°F).
The coldest month (with the lowest average low temperature) is December (44.1°F).

Average pressure in December
Mountain View, CA

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

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

Average wind speed in December
Mountain View, CA

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

The windiest months (with the highest average wind speed) are April and May (6.2mph).
The calmest months (with the lowest average wind speed) are August, September, October and November (4.7mph).

Average humidity in December
Mountain View, CA

Average humidity in December - Mountain View, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are July, September and October (63%).

Average rainfall in December
Mountain View, CA

Average rainfall in December - Mountain View, CA
  • Average rainfall in December: 0.83"

The wettest months (with the highest rainfall) are February, March and December (0.83").
The driest months (with the least rainfall) are June, July and August (0.04").

Average rainfall days in December
Mountain View, CA

Average rainfall days in December - Mountain View, CA
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is March (10 days).
The month with the least rainy days is August (0.4 days).

Average daylight in December /
Average sunshine in December
Mountain View, CA

Average daylight in December / Average sunshine in December - Mountain View, 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
Mountain View, CA

Average sunshine days in December - Mountain View, CA
  • Average sunshine days in December: 21.9 days

The months with the most sunshine days are July and August (29.8 days).
The month with the least sunshine days is March (19.4 days).

Average UV index in December
Mountain View, CA

Average UV index in December - Mountain View, 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 February, November and December (UV index 3).

Average cloud cover in December
Mountain View, CA

Average cloud cover in December - Mountain View, 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
Mountain View, CA

Average visibility in December - Mountain View, 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).

Mountain View, California, USA

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