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 sea temperature 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
Rio del Mar records the coldest temperatures in December, averaging a high of 57.2°F (14°C) and a low of 46.2°F (7.9°C).Humidity
The average relative humidity in December in Rio del Mar is 71%.Rainfall
December is the month with the most rainfall. Rain falls for 10.3 days and accumulates 2.8" (71mm) of precipitation.Ocean temperature
In Rio del Mar, the average seawater temperature in December is 55.6°F (13.1°C).Note: Swimming at temperatures less than 50°F (10°C) in 55.6°F (13.1°C) is feasible with the right swimsuit; if not, expect cold shock and breathlessness. A quick swim at 55.4°F (13°C) without adequate warmth can be discomforting.
Daylight
December has the shortest days of the year, with an average of 9h and 42min of daylight.On the first day of the month, sunrise is at 7:02 am and sunset at 4:51 pm. On the last day of December, in Rio del Mar, sunrise is at 7:20 am and sunset at 5:01 pm PST.
Sunshine
With an average of 5.8h of sunshine, December has the least sunshine of the year in Rio del Mar, California.UV index
In Rio del Mar, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.Note: A daily high UV index of 4 in December leads to these guidelines:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. The Sun's radiation is especially intense around midday; try to stay in shade during this period. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest time of year in Rio del Mar?
What is the average December temperature in Rio del Mar?
What is the average humidity in December in Rio del Mar?
What is the wettest month in Rio del Mar?
How much does it rain in Rio del Mar in December?
How cold is the water in December in Rio del Mar?
What is the month with the shortest days in Rio del Mar?
What is the average length of the day in December in Rio del Mar?
What time are sunrise and sunset in December in Rio del Mar?
What is the month with the least sunshine in Rio del Mar?
How many hours of sunshine does Rio del Mar have in December?
How high is the UV index in December in Rio del Mar?
Average temperature in December
Rio del Mar, CA
- Average high temperature in December: 57.2°F
The warmest months (with the highest average high temperature) are August and September (73°F).
The month with the lowest average high temperature is December (57.2°F).
- Average low temperature in December: 46.2°F
The month with the highest average low temperature is September (55.2°F).
The coldest month (with the lowest average low temperature) is February (45.5°F).
Average pressure in December
Rio del Mar, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in December
Rio del Mar, CA
- Average wind speed in December: 6.2mph
The windiest month (with the highest average wind speed) is April (7.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).
Average humidity in December
Rio del Mar, CA
- Average humidity in December: 71%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (68%).
Average rainfall in December
Rio del Mar, CA
- Average rainfall in December: 2.8"
The wettest month (with the highest rainfall) is December (2.8").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Rio del Mar, CA
- Average rainfall days in December: 10.3 days
The month with the highest number of rainy days is March (13.4 days).
The month with the least rainy days is August (1.2 days).
Average sea temperature in December
Rio del Mar, CA
- Average sea temperature in December: 55.6°F
The best months for swimming (with the highest average sea temperature) are August and September (58.1°F).
The coldest month (with the lowest average sea temperature) is April (53.8°F).
Average daylight in December /
Average sunshine in December
Rio del Mar, CA
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in December: 5h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in December
Rio del Mar, CA
- Average sunshine days in December: 19.5 days
The month with the most sunshine days is August (27.8 days).
The month with the least sunshine days is March (16.4 days).
Average UV index in December
Rio del Mar, CA
- Average UV index in December: 4
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and November (UV index 3).
Average cloud cover in December
Rio del Mar, CA
- Average cloud cover in December: 35
The month with the most cloud cover is March (Cloud cover 38).
The months with the least cloud cover are July and September (Cloud cover 15).
Average visibility in December
Rio del Mar, 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).
Rio del Mar, California, USA
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