December weather forecast
Upland, CA

Weather in December

December, the first month of the winter, in Upland, is still a comfortable month, with temperature in the range of an average low of 45.5°F (7.5°C) and an average high of 62.1°F (16.7°C).

Temperature

The coldest month is December, with an average high-temperature of 62.1°F (16.7°C) and an average low-temperature of 45.5°F (7.5°C).

Humidity

The average relative humidity in December is 51%.

Rainfall

In Upland, California, in December, it is raining for 6.4 days, with typically 1.69" (43mm) of accumulated precipitation. Throughout the year, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.

Snowfall

January, March through December are months without snowfall in Upland.

Daylight

With an average of 9.9h of daylight, December has the shortest days of the year in Upland.

Sunshine

Months with the least sunshine in Upland are February and December, with an average of 6.9h of sunshine.

UV index

The month with the lowest UV index in Upland is December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to the UV radiation for average individuals.
Note: The average daily UV index of 3 in December transform into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the coldest month in Upland?

With an average high-temperature of 62.1°F (16.7°C) and an average low-temperature of 45.5°F (7.5°C), December is the coldest month.

What is the average humidity in December in Upland?

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

How much does it rain in Upland in December?

In December, in Upland, the rain falls for 6.4 days. Throughout December, 1.69" (43mm) of precipitation is accumulated.

When it does not snow in Upland?

January, March through December are months without snowfall.

What is the month with the shortest days in Upland?

The month with the shortest days is December, with an average of 9.9h of daylight.

How many hours of daylight does Upland have in December?

In Upland, California, the average length of the day in December is 9.9h.

What is the month with the least sunshine in Upland?

February and December, with an average of 6.9h of sunshine, are months with the least sunshine in Upland, California.

How many hours of sunshine does Upland have in December?

In Upland, the average sunshine in December is 6.9h.

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

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

What is the UV index intensity in December in Upland?

In December, the average daily maximum UV index in Upland is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to the UV radiation.

Average temperature in December
Upland, CA

Average temperature in December - Upland, CA
  • Average high temperature in December: 62.1°F

The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).

  • Average low temperature in December: 45.5°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

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Average pressure in December
Upland, CA

Average pressure in December - Upland, CA
  • Average pressure in December: 30.07"

The month with the highest atmospheric pressure is January (30.1").
The month with the lowest atmospheric pressure is June (29.86").

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Average wind speed in December
Upland, CA

Average wind speed in December - Upland, CA
  • Average wind speed in December: 5.2mph

The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).

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Average humidity in December
Upland, CA

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

Months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).

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Average rainfall in December
Upland, CA

Average rainfall in December - Upland, CA
  • Average rainfall in December: 1.69"

The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in December
Upland, CA

Average rainfall days in December - Upland, CA
  • Average rainfall days in December: 6.4 days

The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).

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Average snowfall days in December
Upland, CA

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

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

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

Average daylight in December / Average sunshine in December - Upland, CA
  • Average daylight in December: 9.9h

The month with the longest days is June (Average daylight: 14.4h).
The month with the shortest days is December (Average daylight: 9.9h).

  • Average sunshine in December: 6.9h

The month with the most sunshine is July (Average sunshine: 12.1h).
Months with the least sunshine are February and December (Average sunshine: 6.9).

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Average sunshine days in December
Upland, CA

Average sunshine days in December - Upland, CA
  • Average sunshine days in December: 23.2 days

The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).

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Average UV index in December
Upland, CA

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

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).

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Average cloud cover in December
Upland, CA

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

The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in December
Upland, CA

Average visibility in December - Upland, CA
  • Average visibility in December: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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