December weather forecast
Pasadena, CA

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Pasadena City Hall in California, with neon-lit paths and natural gardens, under a perfect blue night sky
Pasadena City Hall in California, with neon-lit paths and natural gardens, under a perfect blue night sky

Weather in December

Pasadena, California, welcomes winter in December with temperatures dropping to an average low of 46.8°F (8.2°C). The brisk chill in the air indicates the onset of the holiday season and closes off the year on a cooler note. Cloud coverage increases and pace of wind takes an upward trajectory, contributing to a more wintery feel. Despite the cooler temperatures, December remains a popular time for visiting Pasadena, thanks to the festive atmosphere enveloping the city. The chillier nights and shorter days make for cozy evenings while the minimal rainfall keeps the exploring spirit alive.

Temperature

Pasadena's coldest weather arrives in December, when temperatures average a high of 61.7°F (16.5°C) and a low of 46.8°F (8.2°C).

Humidity

In December, the average relative humidity in Pasadena is 52%.

Rainfall

In Pasadena, during December, the rain falls for 6.1 days and regularly aggregates up to 1.65" (42mm) of precipitation. Throughout the year, there are 50.1 rainfall days, and 8.5" (216mm) of precipitation is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 54min of daylight.
On the first day of December in Pasadena, sunrise is at 6:40 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 4:53 pm PST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 6.9h of sunshine.

UV index

With an average maximum UV index of 3, December is the month with the lowest UV index in Pasadena. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for average individuals.
Note: In December, a regular UV index of 3 translates into these guidelines:
Put precautions into practice - Guidance to elude sunburn is provided. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
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Frequently asked questions

What is the coldest month in Pasadena?

December is the coldest month in Pasadena, California, with the temperature often reaching an average high of 61.7°F (16.5°C) and an average low of 46.8°F (8.2°C).

What is the average December temperature in Pasadena?

December temperatures in Pasadena, California, vary between a high-temperature of 61.7°F (16.5°C) and a low-temperature of 46.8°F (8.2°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in September is calculated to be 86°F (30°C).

What is the average humidity in December in Pasadena?

In Pasadena, California, the average relative humidity in December is 52%.

How many days does it rain in December in Pasadena?

In December, the rain falls for 6.1 days. Throughout December, 1.65" (42mm) of precipitation is accumulated.

What is the month with the shortest days in Pasadena?

The month with the shortest days in Pasadena, California, is December, with an average of 9h and 54min of daylight.

How many hours of daylight does Pasadena have in December?

The average day length in December in Pasadena is 9h and 55min.

What time are sunrise and sunset in December in Pasadena?

On the first day of December in Pasadena, California, sunrise is at 6:40 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 4:53 pm PST.

What is the month with the least sunshine in Pasadena?

January, February and December, with an average of 6.9h of sunshine, are months with the least sunshine in Pasadena, California.

How many hours of sunshine does Pasadena have in December?

The average sunshine duration in December in Pasadena is 6.9h.

When is the lowest UV index in Pasadena?

With an average maximum UV index of 3, December is the month with the lowest UV index in Pasadena.

What is the UV index intensity in December in Pasadena?

In December, the average daily maximum UV index in Pasadena, California, is 3. A UV Index value of 3 to 5 symbolizes a moderate health threat from exposure to the Sun's 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
Pasadena, CA

Average temperature in December - Pasadena, CA
  • Average high temperature in December: 61.7°F

The warmest month (with the highest average high temperature) is August (87.1°F).
The month with the lowest average high temperature is December (61.7°F).

  • Average low temperature in December: 46.8°F

The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is February (46.6°F).

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Average pressure in December
Pasadena, CA

Average pressure in December - Pasadena, CA
  • Average pressure in December: 30.08"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

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Average wind speed in December
Pasadena, CA

Average wind speed in December - Pasadena, CA
  • Average wind speed in December: 5.2mph

The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).

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Average humidity in December
Pasadena, CA

Average humidity in December - Pasadena, CA
  • Average humidity in December: 52%

The month with the highest relative humidity is June (58%).
The month with the lowest relative humidity is November (47%).

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Average rainfall in December
Pasadena, CA

Average rainfall in December - Pasadena, CA
  • Average rainfall in December: 1.65"

The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in December
Pasadena, CA

Average rainfall days in December - Pasadena, CA
  • Average rainfall days in December: 6.1 days

The month with the highest number of rainy days is March (7.8 days).
The month with the least rainy days is June (1.1 days).

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

Average daylight in December / Average sunshine in December - Pasadena, CA
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 6h and 5min

The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 54min).

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Average sunshine days in December
Pasadena, CA

Average sunshine days in December - Pasadena, CA
  • Average sunshine days in December: 23.4 days

The month with the most sunshine days is June (27.5 days).
The month with the least sunshine days is February (21.5 days).

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Average UV index in December
Pasadena, CA

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

The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).

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Average cloud cover in December
Pasadena, CA

Average cloud cover in December - Pasadena, CA
  • Average cloud cover in December: 21

The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in December
Pasadena, CA

Average visibility in December - Pasadena, 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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Pasadena, California, USA

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