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 month of December sees the lowest average temperatures, reaching 55.2°F (12.9°C) at the peak and 43.2°F (6.2°C) at the low.Humidity
In December, the average relative humidity in Petaluma is 74%.Rainfall
In December, the rain falls for 10.1 days. Throughout December, 2.68" (68mm) of precipitation is accumulated. In Petaluma, during the entire year, the rain falls for 71.1 days and collects up to 15.24" (387mm) of precipitation.Daylight
With an average of 9h and 36min of daylight, December has the shortest days of the year in Petaluma, California.On the first day of December in Petaluma, sunrise is at 7:09 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 5:00 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 5.7h of sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: The daily maximum UV index of 3 in December interprets into the following advice:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. To guard against the harmful effects of the Sun, minimize exposure during midday. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What part of the year is the coldest in Petaluma?
What is the average December temperature in Petaluma?
What is the average humidity in December in Petaluma?
How much does it rain in Petaluma in December?
What is the month with the shortest days in Petaluma?
What is the average length of the day in December in Petaluma?
When is the sunrise / sunset in December in Petaluma?
What is the month with the least sunshine in Petaluma?
How long on average sun shines in December in Petaluma?
What is the month with the lowest UV index in Petaluma?
What is the UV index reading in December in Petaluma?
Average temperature in December
Petaluma, CA
- Average high temperature in December: 55.2°F
The warmest month (with the highest average high temperature) is August (77.9°F).
The month with the lowest average high temperature is December (55.2°F).
- Average low temperature in December: 43.2°F
The month with the highest average low temperature is September (55.2°F).
The coldest month (with the lowest average low temperature) is December (43.2°F).
Average pressure in December
Petaluma, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in December
Petaluma, CA
- Average wind speed in December: 5.4mph
The windiest months (with the highest average wind speed) are April and May (7mph).
The calmest month (with the lowest average wind speed) is November (5mph).
Average humidity in December
Petaluma, CA
- Average humidity in December: 74%
The month with the highest relative humidity is March (77%).
The months with the lowest relative humidity are September and October (65%).
Average rainfall in December
Petaluma, CA
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is February (3.5").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Petaluma, CA
- Average rainfall days in December: 10.1 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is July (1 days).
Average daylight in December /
Average sunshine in December
Petaluma, 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: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days in December
Petaluma, CA
- Average sunshine days in December: 20.2 days
The month with the most sunshine days is July (28.4 days).
The month with the least sunshine days is March (17.2 days).
Average UV index in December
Petaluma, 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
Petaluma, CA
- Average cloud cover in December: 37
The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is July (Cloud cover 10).
Average visibility in December
Petaluma, 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).
Petaluma, California, USA
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