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
The coldest time of the year is December, with temperatures averaging a high of 55.9°F (13.3°C) and a low of 46.6°F (8.1°C).Humidity
In Atherton, the average relative humidity in December is 72%.Rainfall
In Atherton, in December, during 10.2 rainfall days, 2.05" (52mm) of precipitation is typically accumulated. Throughout the year, there are 73.4 rainfall days, and 11.89" (302mm) of precipitation is accumulated.Daylight
December has the shortest days of the year in Atherton, California, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:05 am and sunset at 4:50 pm. On the last day of December, in Atherton, sunrise is at 7:23 am and sunset at 5:01 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 5.8h of sunshine.UV index
The months with the lowest UV index are November and December, with an average maximum UV index of 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.Note: An average UV index of 3 in December transforms into this advice:
Act with care - Obligation to protect against skin and eye damage is highlighted. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Frequently asked questions
What part of the year is the coldest in Atherton?
What are December temperatures in Atherton?
What is the average humidity in December in Atherton?
How many days does it rain in December in Atherton?
What is the month with the shortest days in Atherton?
How many hours of daylight does Atherton have in December?
What time are sunrise and sunset in December in Atherton?
What is the month with the least sunshine in Atherton?
How long on average sun shines in December in Atherton?
When is the lowest UV index in Atherton?
What is the UV index intensity in December in Atherton?
Average temperature in December
Atherton, CA
- Average high temperature in December: 55.9°F
The warmest months (with the highest average high temperature) are July and August (73°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in December: 46.6°F
The month with the highest average low temperature is September (56.7°F).
The coldest month (with the lowest average low temperature) is February (46°F).
Average pressure in December
Atherton, 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
Atherton, CA
- Average wind speed in December: 6.5mph
The windiest month (with the highest average wind speed) is April (7.5mph).
The calmest months (with the lowest average wind speed) are August, September and October (5.5mph).
Average humidity in December
Atherton, CA
- Average humidity in December: 72%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (68%).
Average rainfall in December
Atherton, CA
- Average rainfall in December: 2.05"
The wettest month (with the highest rainfall) is February (2.36").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Atherton, CA
- Average rainfall days in December: 10.2 days
The month with the highest number of rainy days is March (12.8 days).
The month with the least rainy days is August (0.8 days).
Average daylight in December /
Average sunshine in December
Atherton, 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 36min).
- Average sunshine in December: 5h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in December
Atherton, CA
- Average sunshine days in December: 19.3 days
The month with the most sunshine days is August (27.6 days).
The month with the least sunshine days is March (17.5 days).
Average UV index in December
Atherton, CA
- Average UV index in December: 3
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are November and December (UV index 3).
Average cloud cover in December
Atherton, CA
- Average cloud cover in December: 34
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in December
Atherton, 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).
Atherton, California, USA
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