December weather forecast
Mission Viejo, CA

Share
The calm waters on Lake Mission Viejo, California,
The calm waters on Lake Mission Viejo, California,

Weather in December

The first month of the winter, December, is still a comfortable month in Mission Viejo, California, with an average temperature fluctuating between 63°F (17.2°C) and 49.8°F (9.9°C).

Temperature

Mission Viejo experiences its lowest temperatures in December, with an average peak of 63°F (17.2°C) and a low of 49.8°F (9.9°C).

Humidity

The average relative humidity in December is 60%.

Rainfall

December is the month with the most rainfall. Rain falls for 6.7 days and accumulates 0.98" (25mm) 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 6:37 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:54 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

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.
Note: The daily high UV index of 4 during December translates into the following recommendations:
Prioritize safety - Recommendations to avert sunburn are shared. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest?

December is the month when Mission Viejo experiences its coldest temperatures, averaging a high of 63°F (17.2°C) and a low of 49.8°F (9.9°C).

What are December temperatures?

The high-temperature during December is 63°F (17.2°C) and the low-temperature is 49.8°F (9.9°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in August is evaluated at 84.2°F (29°C).

What is the average humidity in December?

The average relative humidity in December is 60%.

What is the rainiest month?

December is the month with the most rainfall. Rain falls for 6.7 days and accumulates 0.98" (25mm) of precipitation.

How much does it rain in December?

In Mission Viejo, in December, during 6.7 rainfall days, 0.98" (25mm) of precipitation is typically accumulated.

What is the month with the shortest days in Mission Viejo?

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 Mission Viejo?

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

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:37 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 4:53 pm PST.

What is the month with the least sunshine?

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

How long on average sun shines in December?

In Mission Viejo, the average sunshine duration in December is 6.6h.

When is the lowest UV index in Mission Viejo?

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

What is the UV index reading in December?

In December, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability 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
Mission Viejo, CA

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

The warmest month (with the highest average high temperature) is August (80.8°F).
The month with the lowest average high temperature is December (63°F).

  • Average low temperature in December: 49.8°F

The month with the highest average low temperature is August (64°F).
The coldest month (with the lowest average low temperature) is February (48.7°F).

Average pressure in December
Mission Viejo, CA

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

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

Average wind speed in December
Mission Viejo, CA

Average wind speed in December - Mission Viejo, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).

Average humidity in December
Mission Viejo, CA

Average humidity in December - Mission Viejo, CA
  • Average humidity in December: 60%

The months with the highest relative humidity are May and June (70%).
The month with the lowest relative humidity is November (56%).

Average rainfall in December
Mission Viejo, CA

Average rainfall in December - Mission Viejo, CA
  • Average rainfall in December: 0.98"

The wettest month (with the highest rainfall) is December (0.98").
The driest month (with the least rainfall) is June (0.08").

Average rainfall days in December
Mission Viejo, CA

Average rainfall days in December - Mission Viejo, CA
  • Average rainfall days in December: 6.7 days

The month with the highest number of rainy days is March (8.4 days).
The month with the least rainy days is June (2.3 days).

Average daylight in December /
Average sunshine in December
Mission Viejo, CA

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

The month with the longest days is June (Average daylight: 14h and 18min).
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
Mission Viejo, CA

Average sunshine days in December - Mission Viejo, CA
  • Average sunshine days in December: 22.6 days

The months with the most sunshine days are January and August (24.4 days).
The month with the least sunshine days is May (19.5 days).

Average UV index in December
Mission Viejo, CA

Average UV index in December - Mission Viejo, 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
Mission Viejo, CA

Average cloud cover in December - Mission Viejo, CA
  • Average cloud cover in December: 25

The months with the most cloud cover are March and December (Cloud cover 25).
The month with the least cloud cover is August (Cloud cover 7).

Average visibility in December
Mission Viejo, CA

Average visibility in December - Mission Viejo, 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).

Mission Viejo, California, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location