December weather forecast
Jamacha, CA

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Weather in December

The first month of the winter, December, is still a refreshing month in Jamacha, California, with an average temperature fluctuating between 47.3°F (8.5°C) and 63°F (17.2°C).

Temperature

December, on average, is the coldest month, registering a high temperature of 63°F (17.2°C) and a low of 47.3°F (8.5°C).

Humidity

In Jamacha, California, the average relative humidity in December is 58%.

Rainfall

In Jamacha, in December, it is raining for 6.2 days, with typically 1.34" (34mm) of accumulated precipitation. Throughout the year, there are 60.6 rainfall days, and 8.66" (220mm) of precipitation is accumulated.

Daylight

With an average of 10h and 0min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 6:32 am and sunset at 4:41 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 4:52 pm PST.

Sunshine

With an average of 6.7h of sunshine, December has the least sunshine of the year.

UV index

With an average maximum UV index of 3, December is the month with the lowest UV index. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.
Note: In December, the maximum UV index of 3 suggests these recommendations:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Updated: Jul 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

December tends to be the coldest month, with temperatures averaging a daily high of 63°F (17.2°C) and a low of 47.3°F (8.5°C).

What are the temperatures in December?

An average high-temperature, in December, in Jamacha, is 63°F (17.2°C) and the average low-temperature is 47.3°F (8.5°C). In September, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which calculates the temperature value influenced by the moisture in the air, is calculated to be 84.2°F (29°C).

What is the average humidity in December?

The average relative humidity in December in Jamacha is 58%.

How many days does it rain in December?

In Jamacha, in December, during 6.2 rainfall days, 1.34" (34mm) of precipitation is typically accumulated.

What is the month with the shortest days?

With an average of 10h and 0min of daylight, December has the shortest days of the year.

How many hours of daylight does Jamacha have in December?

The average day length in December is 10h and 2min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 6:32 am and sunset at 4:41 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 4:52 pm PST.

What is the month with the least sunshine?

With an average of 6.7h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December?

In Jamacha, the average sunshine duration in December is 6.7h.

What is the month with the lowest UV index in Jamacha?

December is the month with the lowest UV index, with an average maximum UV index of 3.

What is the UV index reading in December?

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

Average temperature in December
Jamacha, CA

Average temperature in December - Jamacha, CA
  • Average high temperature in December: 63°F

The warmest month (with the highest average high temperature) is August (84.2°F).
The month with the lowest average high temperature is December (63°F).

  • Average low temperature in December: 47.3°F

The month with the highest average low temperature is August (66.2°F).
The coldest months (with the lowest average low temperature) are February and December (47.3°F).

Average pressure in December
Jamacha, CA

Average pressure in December - Jamacha, CA
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is January (30.08"Hg).
The months with the lowest atmospheric pressure are June and September (29.87"Hg).

Average wind speed in December
Jamacha, CA

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

The windiest months (with the highest average wind speed) are April and May (5.5mph).
The calmest months (with the lowest average wind speed) are September and October (4.3mph).

Average humidity in December
Jamacha, CA

Average humidity in December - Jamacha, CA
  • Average humidity in December: 58%

The month with the highest relative humidity is May (65%).
The month with the lowest relative humidity is November (52%).

Average rainfall in December
Jamacha, CA

Average rainfall in December - Jamacha, CA
  • Average rainfall in December: 1.34"

The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.08").

Average rainfall days in December
Jamacha, CA

Average rainfall days in December - Jamacha, CA
  • Average rainfall days in December: 6.2 days

The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1.3 days).

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

Average daylight in December / Average sunshine in December - Jamacha, CA
  • Average daylight in December: 10h and 0min

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in December: 6h and 4min

The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).

Average sunshine days in December
Jamacha, CA

Average sunshine days in December - Jamacha, CA
  • Average sunshine days in December: 23.4 days

The month with the most sunshine days is June (27.8 days).
The month with the least sunshine days is July (20.3 days).

Average UV index in December
Jamacha, CA

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

The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in December
Jamacha, CA

Average cloud cover in December - Jamacha, CA
  • Average cloud cover in December: 23

The months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 6).

Average visibility in December
Jamacha, CA

Average visibility in December - Jamacha, 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).

Jamacha, California, USA

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