Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
February and December are identified as the coldest months, with an average high-temperature of 63.3°F (17.4°C).Humidity
In San Marcos, the average relative humidity in December is 60%.Rainfall
December is the month with the most rainfall in San Marcos. Rain falls for 5.9 days and accumulates 1.22" (31mm) of precipitation.Daylight
With an average of 10h and 0min of daylight, December has the shortest days of the year in San Marcos.On the first day of the month, sunrise is at 6:34 am and sunset at 4:41 pm. On the last day of December, in San Marcos, sunrise is at 6:51 am and sunset at 4:52 pm PST.
Sunshine
With an average of 6.8h of sunshine, December has the least sunshine of the year.UV index
January through March, November and December, with an average maximum UV index of 4, are months with the lowest UV index in San Marcos. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: The maximum daily UV index of 4 in December converts into the following recommendations:
Exercise care. People with light skin might get burns in fewer than 30 minutes. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest time of year in San Marcos?
What are December temperatures in San Marcos?
What is the average humidity in December in San Marcos?
What is the rainiest month in San Marcos?
How many days does it rain in December in San Marcos?
What is the month with the shortest days in San Marcos?
What is the average length of the day in December in San Marcos?
What time are sunrise and sunset in December in San Marcos?
What is the month with the least sunshine in San Marcos?
How many hours of sunshine does San Marcos have in December?
When is the lowest UV index in San Marcos?
What is the UV index reading in December in San Marcos?
Average temperature in December
San Marcos, CA
- Average high temperature in December: 63.3°F
The warmest month (with the highest average high temperature) is August (81.9°F).
The months with the lowest average high temperature are February and December (63.3°F).
- Average low temperature in December: 48.2°F
The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is February (48°F).
Average pressure in December
San Marcos, CA
- Average pressure in December: 30.06"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in December
San Marcos, CA
- Average wind speed in December: 5mph
The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is October (4.4mph).
Average humidity in December
San Marcos, CA
- Average humidity in December: 60%
The month with the highest relative humidity is May (70%).
The month with the lowest relative humidity is November (56%).
Average rainfall in December
San Marcos, CA
- Average rainfall in December: 1.22"
The wettest month (with the highest rainfall) is December (1.22").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in December
San Marcos, CA
- Average rainfall days in December: 5.9 days
The month with the highest number of rainy days is March (7.8 days).
The month with the least rainy days is June (1.2 days).
Average daylight in December /
Average sunshine in December
San Marcos, 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 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 48min).
Average sunshine days in December
San Marcos, CA
- Average sunshine days in December: 22.5 days
The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is February (20 days).
Average UV index in December
San Marcos, 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
San Marcos, CA
- Average cloud cover in December: 23
The months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 7).
Average visibility in December
San Marcos, 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).
San Marcos, California, USA
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