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 period is December, when temperatures fluctuate between an average high of 55.4°F (13°C) and a low of 43.2°F (6.2°C).Humidity
In Port Costa, the average relative humidity in December is 71%.Rainfall
In Port Costa, California, in December, during 8.5 rainfall days, 0.79" (20mm) of precipitation is typically accumulated. In Port Costa, during the entire year, the rain falls for 56.9 days and collects up to 4.88" (124mm) of precipitation.Daylight
December has the shortest days of the year, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:06 am and sunset at 4:49 pm. On the last day of December, sunrise is at 7:24 am and sunset at 4:59 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 5.7h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 3 in December converts into the following recommendations:
Adopt protective measures - Suggestions to resist sunburn are offered. To guard against the harmful effects of the Sun, minimize exposure during midday. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Frequently asked questions
What part of the year is the coldest in Port Costa?
What is the average December temperature in Port Costa?
What is the average humidity in December in Port Costa?
How many days does it rain in December in Port Costa?
What is the month with the shortest days in Port Costa?
How many hours of daylight does Port Costa have in December?
When are sunrise and sunset in December in Port Costa?
What is the month with the least sunshine in Port Costa?
How many hours of sunshine does Port Costa have in December?
What is the month with the lowest UV index in Port Costa?
What is the UV index intensity in December in Port Costa?
Average temperature in December
Port Costa, CA
- Average high temperature in December: 55.4°F
The warmest months (with the highest average high temperature) are July and September (80.1°F).
The month with the lowest average high temperature is December (55.4°F).
- Average low temperature in December: 43.2°F
The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is January (43°F).
Average pressure in December
Port Costa, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Port Costa, CA
- Average wind speed in December: 5.2mph
The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).
Average humidity in December
Port Costa, CA
- Average humidity in December: 71%
The month with the highest relative humidity is March (75%).
The months with the lowest relative humidity are September and October (60%).
Average rainfall in December
Port Costa, CA
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is February (1.14").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Port Costa, CA
- Average rainfall days in December: 8.5 days
The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is August (0.9 days).
Average daylight in December /
Average sunshine in December
Port Costa, CA
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 4min
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 42min).
Average sunshine days in December
Port Costa, CA
- Average sunshine days in December: 20.8 days
The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (18.8 days).
Average UV index in December
Port Costa, CA
- Average UV index in December: 3
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Port Costa, CA
- Average cloud cover in December: 36
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in December
Port Costa, 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).
Port Costa, California, USA
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