December weather forecast
Byron, CA

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Weather in December

December, the first month of the winter in Byron, is still a cool month, with an average temperature ranging between max 55°F (12.8°C) and min 41.7°F (5.4°C).

Temperature

December is the month that records the lowest temperatures, with averages ranging from a high of 55°F (12.8°C) to a low of 41.7°F (5.4°C).

Humidity

In Byron, the average relative humidity in December is 71%.

Rainfall

In Byron, in December, during 9.3 rainfall days, 1.57" (40mm) of precipitation is typically accumulated. Throughout the year, there are 62 rainfall days, and 10.16" (258mm) of precipitation is accumulated.

Snowfall

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

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:57 pm PST.

Sunshine

With an average of 5.8h of sunshine, December has the least sunshine of the year in Byron.

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 vulnerability from unsafe exposure to UV radiation for the average person.
Note: The daily high UV index of 3 during December translates into the following recommendations:
Take necessary precautions - Protection from skin and eye injury is mandatory. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.

Frequently asked questions

What is the coldest time of year?

The coldest period is December, when temperatures fluctuate between an average high of 55°F (12.8°C) and a low of 41.7°F (5.4°C).

What is the usual temperature for Byron in December?

During December, Byron experiences an average high-temperature of 55°F (12.8°C) and a low-temperature of 41.7°F (5.4°C). In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 71%.

How many days does it rain in December?

In Byron, during December, the rain falls for 9.3 days and regularly aggregates up to 1.57" (40mm) of precipitation.

What is the snowiest month?

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

When does it start snowing?

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

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 36min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 35min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:57 pm PST.

What is the month with the least sunshine?

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

How long on average sun shines in December?

In December, the average sunshine duration is 5.8h.

When is 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 intensity in December?

The average daily maximum UV index in December is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unprotected exposure to UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
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
Byron, CA

Average temperature in December - Byron, CA
  • Average high temperature in December: 55°F

The warmest month (with the highest average high temperature) is July (88.5°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in December: 41.7°F

The month with the highest average low temperature is September (57.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).

Average pressure in December
Byron, CA

Average pressure in December - Byron, 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
Byron, CA

Average wind speed in December - Byron, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is June (7.8mph).
The calmest months (with the lowest average wind speed) are January and November (4.5mph).

Average humidity in December
Byron, CA

Average humidity in December - Byron, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is January (74%).
The month with the lowest relative humidity is September (52%).

Average rainfall in December
Byron, CA

Average rainfall in December - Byron, CA
  • Average rainfall in December: 1.57"

The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Byron, CA

Average rainfall days in December - Byron, CA
  • Average rainfall days in December: 9.3 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.8 days).

Average snowfall days in December
Byron, CA

Average snowfall days in December - Byron, 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
Byron, CA

Average daylight in December / Average sunshine in December - Byron, 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 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

Average sunshine days in December
Byron, CA

Average sunshine days in December - Byron, CA
  • Average sunshine days in December: 21.1 days

The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is March (17.7 days).

Average UV index in December
Byron, CA

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

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in December
Byron, CA

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

The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).

Average visibility in December
Byron, CA

Average visibility in December - Byron, 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).

Byron, California, USA

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