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December Weather in Mountain View, United States

Last updated: June 24, 2025

In December, the average temperature in Mountain View, United States hovers around 7°C (44°F). Be prepared for a temperature range that can dip as low as -10°C (15°F) and soar up to 29°C (84°F). Expect about 29 mm (1.1 in) of precipitation over the course of 3 days, with an average humidity level of 84%.

December Temperature in Mountain View

In December in Mountain View, the average temperature is 7°C (44°F), with maximums reaching up to 29°C (84°F) and minimums dipping as low as -10°C (15°F). Be prepared for a wide range of temperatures when planning your travels!

December Weather in Mountain View: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Mountain View, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mountain View, December typically has an average temperature of 7°C (44°F), with highs reaching up to 29°C (84°F) and lows dropping to around -10°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec394154607080838275625044
Data source: Temperature data for Mountain View generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Mountain View

In Mountain View in December, the precipitation amount is 29 mm (1.1 in) over the course of 3 days.

December Precipitation Trends in Mountain View

The chart displays monthly precipitation patterns in Mountain View, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Mountain View, December typically receives around 29 mm (1.1 inches) of precipitation spread over approximately 3 days.
JanFebMarAprMayJunJulAugSepOctNovDec3931659414163374478812129
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Mountain View

In Mountain View in December humidity is 84%. With an average temperature of 7°C (44°F), this humidity feels like a damp chill that seeps into your bones, making it uncomfortable for traveling and requiring extra layers to stay warm and dry.

December Average Humidity in Mountain View

This chart illustrates the average monthly humidity levels in Mountain View, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Mountain View is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%76%70%72%82%82%80%72%64%71%81%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Mountain View

In Mountain View in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Mountain View for better planning.

Maximum UV Index Levels in Mountain View for December

The chart shows the monthly maximum UV Index (UVI) for Mountain View in December, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In December, the maximum UV index in Mountain View typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46810111112119754
Data source: Mountain View December UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How December Weather in Mountain View Compares to Other Months

Weather in Mountain View varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Mountain View, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Mountain View, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)39 mm (1.5 inches)76%moderate
February Weather5°C (41°F)31 mm (1.2 inches)76%high
March Weather12°C (54°F)65 mm (2.6 inches)70%very high
April Weather16°C (60°F)94 mm (3.7 inches)72%very high
May Weather21°C (70°F)141 mm (5.6 inches)82%extreme
June Weather26°C (80°F)63 mm (2.5 inches)82%extreme
July Weather29°C (84°F)37 mm (1.5 inches)80%extreme
August Weather28°C (82°F)44 mm (1.7 inches)72%extreme
September Weather24°C (75°F)78 mm (3.1 inches)64%very high
October Weather17°C (62°F)81 mm (3.2 inches)71%high
November Weather10°C (50°F)21 mm (0.8 inches)81%moderate
December Weather7°C (44°F)29 mm (1.1 inches)84%moderate

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