December weather forecast
Thermalito, CA

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Weather in December

December, the first month of the winter in Thermalito, is also a fresh month, with an average temperature ranging between max 54.5°F (12.5°C) and min 40.6°F (4.8°C).

Temperature

December is the coldest month, with an average high-temperature of 54.5°F (12.5°C) and an average low-temperature of 40.6°F (4.8°C).

Humidity

The average relative humidity in December is 67%.

Rainfall

In Thermalito, in December, during 11.1 rainfall days, 4.33" (110mm) of precipitation is typically accumulated. Throughout the year, there are 80.4 rainfall days, and 24.21" (615mm) of precipitation is accumulated.

Snowfall

The only month with snowfall is December. December has the most snowfall days of the year. Snow falls for 0.1 days.

Daylight

December has the shortest days of the year, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:08 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:52 pm PST.

Sunshine

The month with the least sunshine is December, with an average of 5.8h 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 of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: A maximum high daily UV index of 3 during December translates into the following directions:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Updated: Jun 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest?

Thermalito reaches its average lowest temperatures in December, measuring 54.5°F (12.5°C) at the peak and 40.6°F (4.8°C) at the lowest.

What is the usual temperature for Thermalito in December?

December temperatures in Thermalito vary between a high-temperature of 54.5°F (12.5°C) and a low-temperature of 40.6°F (4.8°C). In June, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is evaluated at 87.8°F (31°C).

What is the average humidity in December?

In December, the average relative humidity is 67%.

How many days does it rain in December?

In Thermalito, during December, the rain falls for 11.1 days and regularly aggregates up to 4.33" (110mm) of precipitation.

When does it snow the most?

The month with the most snowfall days is December, when snow falls for 0.1 days.

When does it start to snow?

December is the first month it typically snows. Throughout December, there are 0.1 snowfall days.

What is the month with the shortest days in Thermalito?

With an average of 9h and 24min of daylight, December has the shortest days of the year.

How many hours of daylight does Thermalito have in December?

In Thermalito, the average day length in December is 9h and 26min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:08 am and sunset at 4:43 pm. On the last day of the month, in Thermalito, sunrise is at 7:26 am and sunset at 4:52 pm PST.

What is the month with the least sunshine?

December has the least sunshine of the year, with an average of 5.8h of sunshine.

How long on average sun shines in December?

In Thermalito, the average sunshine duration in December is 5.8h.

What are the months with the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3.

What is the UV index reading in December?

In December, the average daily maximum UV index in Thermalito is 3. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Thermalito, CA

Average temperature in December - Thermalito, CA
  • Average high temperature in December: 54.5°F

The warmest month (with the highest average high temperature) is July (95.9°F).
The month with the lowest average high temperature is December (54.5°F).

  • Average low temperature in December: 40.6°F

The month with the highest average low temperature is July (63.7°F).
The coldest month (with the lowest average low temperature) is December (40.6°F).

Average pressure in December
Thermalito, CA

Average pressure in December - Thermalito, CA
  • Average pressure in December: 30.14"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in December
Thermalito, CA

Average wind speed in December - Thermalito, CA
  • Average wind speed in December: 5.3mph

The windiest month (with the highest average wind speed) is March (6.3mph).
The calmest months (with the lowest average wind speed) are August and November (5.2mph).

Average humidity in December
Thermalito, CA

Average humidity in December - Thermalito, CA
  • Average humidity in December: 67%

The month with the highest relative humidity is March (72%).
The month with the lowest relative humidity is July (33%).

Average rainfall in December
Thermalito, CA

Average rainfall in December - Thermalito, CA
  • Average rainfall in December: 4.33"

The wettest month (with the highest rainfall) is March (4.61").
The driest month (with the least rainfall) is July (0.04").

Average rainfall days in December
Thermalito, CA

Average rainfall days in December - Thermalito, CA
  • Average rainfall days in December: 11.1 days

The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is July (1.3 days).

Average snowfall days in December
Thermalito, CA

Average snowfall days in December - Thermalito, CA
  • Average snowfall days in December: 0.1 days

The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).

Average daylight in December /
Average sunshine in December
Thermalito, CA

Average daylight in December / Average sunshine in December - Thermalito, CA
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in December: 5h 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: 5h and 48min).

Average sunshine days in December
Thermalito, CA

Average sunshine days in December - Thermalito, CA
  • Average sunshine days in December: 19.2 days

The month with the most sunshine days is July (29.3 days).
The month with the least sunshine days is March (15.5 days).

Average UV index in December
Thermalito, CA

Average UV index in December - Thermalito, CA
  • Average UV index in December: 3

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in December
Thermalito, CA

Average cloud cover in December - Thermalito, CA
  • Average cloud cover in December: 35

The month with the most cloud cover is March (Cloud cover 38).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in December
Thermalito, CA

Average visibility in December - Thermalito, 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).

Thermalito, California, USA

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