December weather forecast
Irvine, CA

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The neon-lit city of Irvine in California, with highway lights and the distant hill ranges and skyscape
The neon-lit city of Irvine in California, with highway lights and the distant hill ranges and skyscape

Weather in December

Ending the cycle of seasons in Irvine, December is synonymous with cooler temperatures and the holiday season. Despite the drop in temperatures, the conditions remain relatively mild compared to other regions of the country. December brings the highest amount of rainfall for the year, with an average precipitation of 1.54" (39mm). Irvine's Christmas festivities and New Year’s celebrations fill the city with a sense of warmth and merriment. The city bids adieu to the year amidst twinkling lights, cozy fireplaces, holiday markets, and a blanket of tranquillity.

Temperature

Irvine's temperature records reveal December as the coldest month, marked by average highs of 63°F (17.2°C) and lows of 51.8°F (11°C).

Humidity

In Irvine, the average relative humidity in December is 60%.

Rainfall

December is the month with the most rainfall. Rain falls for 6.9 days and accumulates 1.54" (39mm) of precipitation.

Daylight

December has the shortest days of the year, with an average of 10h and 0min of daylight.
On the first day of December, sunrise is at 6:38 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 4:53 pm PST.

Sunshine

The month with the least sunshine is December, with an average of 6.6h of sunshine.

UV index

January through March, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 4 in December transforms into the following instructions:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Updated: Jun 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

December, recording an average high temperature of 63°F (17.2°C) and a low temperature of 51.8°F (11°C), is Irvine's coldest month.

What is the temperature in December?

Irvine in December has an average high-temperature of 63°F (17.2°C) and an average low-temperature of 51.8°F (11°C).

What is the average humidity in December?

The average relative humidity in December is 60%.

What is the rainiest month?

The month with the most rainfall is December, when the rain falls for 6.9 days and typically aggregates up to 1.54" (39mm) of precipitation.

How many days does it rain in December?

In Irvine, California, in December, during 6.9 rainfall days, 1.54" (39mm) of precipitation is typically accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 10h and 0min of daylight.

What is the average length of the day in December?

In Irvine, the average day length in December is 9h and 58min.

What time are sunrise and sunset in December?

On the first day of December, sunrise is at 6:38 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 4:53 pm PST.

What is the month with the least sunshine?

With an average of 6.6h of sunshine, December has the least sunshine of the year.

How many hours of sunshine does Irvine have in December?

In December, the average sunshine duration is 6.6h.

What are the months with the lowest UV index?

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 4.

What is the UV index intensity in December?

In December, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health from 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
Irvine, CA

Average temperature in December - Irvine, CA
  • Average high temperature in December: 63°F

The warmest month (with the highest average high temperature) is August (79.9°F).
The month with the lowest average high temperature is December (63°F).

  • Average low temperature in December: 51.8°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 (50.5°F).

Average pressure in December
Irvine, CA

Average pressure in December - Irvine, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in December
Irvine, CA

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

The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest months (with the lowest average wind speed) are September and October (4.8mph).

Average humidity in December
Irvine, CA

Average humidity in December - Irvine, CA
  • Average humidity in December: 60%

The month with the highest relative humidity is June (71%).
The month with the lowest relative humidity is November (56%).

Average rainfall in December
Irvine, CA

Average rainfall in December - Irvine, CA
  • Average rainfall in December: 1.54"

The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is June (0.08").

Average rainfall days in December
Irvine, CA

Average rainfall days in December - Irvine, CA
  • Average rainfall days in December: 6.9 days

The month with the highest number of rainy days is March (7.9 days).
The month with the least rainy days is June (2.2 days).

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

Average daylight in December / Average sunshine in December - Irvine, CA
  • Average daylight in December: 10h and 0min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in December: 6h and 4min

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: 6h and 36min).

Average sunshine days in December
Irvine, CA

Average sunshine days in December - Irvine, CA
  • Average sunshine days in December: 22.5 days

The month with the most sunshine days is January (24.5 days).
The month with the least sunshine days is May (19.7 days).

Average UV index in December
Irvine, CA

Average UV index in December - Irvine, CA
  • Average UV index in December: 4

The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).

Average cloud cover in December
Irvine, CA

Average cloud cover in December - Irvine, CA
  • Average cloud cover in December: 24

The month with the most cloud cover is December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 7).

Average visibility in December
Irvine, CA

Average visibility in December - Irvine, 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).

Irvine, California, USA

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