December weather forecast
Fontana, CA

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Weather in December

December, the first month of the winter in Fontana, is still a comfortable month, with an average temperature ranging between max 60.8°F (16°C) and min 44.2°F (6.8°C).

Temperature

With its high average temperature of 60.8°F (16°C) and a low of 44.2°F (6.8°C), December is regarded as the coldest month.

Humidity

In Fontana, the average relative humidity in December is 51%.

Rainfall

In Fontana, during December, the rain falls for 5.9 days and regularly aggregates up to 1.5" (38mm) of precipitation. In Fontana, during the entire year, the rain falls for 48.1 days and collects up to 6.89" (175mm) of precipitation.

Snowfall

In Fontana, snow does not fall in January, March through December.

Daylight

With an average of 9h and 54min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 6:37 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 4:50 pm PST.

Sunshine

December has the least sunshine of the year, with an average of 6.9h of sunshine.

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 medium vulnerability 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:
Make use of precautions - Suggestions to resist sunburn are communicated. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Updated: Jun 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

During the coldest month in Fontana, December, temperatures average a high of 60.8°F (16°C) and a low of 44.2°F (6.8°C).

What are December temperatures in Fontana?

December temperatures vary between a high-temperature of 60.8°F (16°C) and a low-temperature of 44.2°F (6.8°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in September is calculated to be 89.6°F (32°C).

What is the average humidity in December?

In Fontana, the average relative humidity in December is 51%.

How much does it rain in December?

In December, the rain falls for 5.9 days. Throughout December, 1.5" (38mm) of precipitation is accumulated.

When it does not snow?

January, March through December are months without snowfall.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 54min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 56min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 6:37 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 4:50 pm PST.

What is the month with the least sunshine?

The month with the least sunshine is December, with an average of 6.9h of sunshine.

How many hours of sunshine does Fontana have in December?

The average sunshine duration in December is 6.9h.

When is the lowest UV index in Fontana?

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

What is the UV index reading in December in Fontana?

In December, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a moderate health threat from unsafe 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
Fontana, CA

Average temperature in December - Fontana, CA
  • Average high temperature in December: 60.8°F

The warmest month (with the highest average high temperature) is August (92.1°F).
The month with the lowest average high temperature is December (60.8°F).

  • Average low temperature in December: 44.2°F

The month with the highest average low temperature is August (67.3°F).
The coldest months (with the lowest average low temperature) are February and December (44.2°F).

Average pressure in December
Fontana, CA

Average pressure in December - Fontana, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).

Average wind speed in December
Fontana, CA

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

The windiest months (with the highest average wind speed) are April and May (6mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).

Average humidity in December
Fontana, CA

Average humidity in December - Fontana, CA
  • Average humidity in December: 51%

The months with the highest relative humidity are February, March and May (52%).
The month with the lowest relative humidity is August (39%).

Average rainfall in December
Fontana, CA

Average rainfall in December - Fontana, CA
  • Average rainfall in December: 1.5"

The wettest month (with the highest rainfall) is February (1.57").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in December
Fontana, CA

Average rainfall days in December - Fontana, CA
  • Average rainfall days in December: 5.9 days

The month with the highest number of rainy days is March (7.5 days).
The month with the least rainy days is June (1.2 days).

Average snowfall days in December
Fontana, CA

Average snowfall days in December - Fontana, CA
  • Average snowfall days in December: 0 days

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

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

Average daylight in December / Average sunshine in December - Fontana, CA
  • Average daylight in December: 9h and 5min

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

  • Average sunshine in December: 6h and 5min

The months with the most sunshine are June, July and August (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 54min).

Average sunshine days in December
Fontana, CA

Average sunshine days in December - Fontana, CA
  • Average sunshine days in December: 23.8 days

The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (21.1 days).

Average UV index in December
Fontana, CA

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

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in December
Fontana, CA

Average cloud cover in December - Fontana, CA
  • Average cloud cover in December: 21

The months with the most cloud cover are February, March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 4).

Average visibility in December
Fontana, CA

Average visibility in December - Fontana, 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).

Fontana, California, USA

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