December weather forecast
Spring Valley, CA

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Weather in December

The first month of the winter, December, is still a comfortable month in Spring Valley, California, with temperature in the range of an average low of 49.3°F (9.6°C) and an average high of 64.4°F (18°C).

Temperature

The coldest period tends to be December, when average temperatures fluctuate between a high of 64.4°F (18°C) and a low of 49.3°F (9.6°C).

Humidity

In December, the average relative humidity is 59%.

Rainfall

In Spring Valley, in December, it is raining for 3.5 days, with typically 0.51" (13mm) of accumulated precipitation. Throughout the year, there are 33 rainfall days, and 2.52" (64mm) of precipitation is accumulated.

Daylight

The month with the shortest days is December, with an average of 10h and 0min of daylight.
On the first day of the month, sunrise is at 6:32 am and sunset at 4:41 pm. On the last day of December, sunrise is at 6:50 am and sunset at 4:52 pm PST.

Sunshine

February and December, with an average of 6.7h of sunshine, are months with the least sunshine in Spring Valley.

UV index

January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The maximum UV index, 4 during December, leads to the following recommendations:
Act with care - The need to guard against sun damage is communicated. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Updated: Jul 19, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

Temperature records mark December as the coldest month, with highs averaging 64.4°F (18°C) and lows at 49.3°F (9.6°C).

What are the temperatures in December?

The high-temperature, in December, in Spring Valley, records 64.4°F (18°C), while the low-temperature is 49.3°F (9.6°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 evaluated at 84.2°F (29°C).

What is the average humidity in December in Spring Valley?

In Spring Valley, the average relative humidity in December is 59%.

How many days does it rain in December in Spring Valley?

In Spring Valley, in December, it is raining for 3.5 days, with typically 0.51" (13mm) of accumulated precipitation.

What is the month with the shortest days?

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

What is the average length of the day in December?

In December, the average day length is 10h and 2min.

What time are sunrise and 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 6:50 am and sunset at 4:52 pm PST.

What are the months with the least sunshine in Spring Valley?

February and December, with an average of 6.7h of sunshine, are months with the least sunshine.

How many hours of sunshine does Spring Valley have in December?

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

When is the lowest UV index?

January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index.

What is the UV index reading in December?

In December, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium hazard to health from unsafe 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
Spring Valley, CA

Average temperature in December - Spring Valley, CA
  • Average high temperature in December: 64.4°F

The warmest month (with the highest average high temperature) is August (82.9°F).
The month with the lowest average high temperature is December (64.4°F).

  • Average low temperature in December: 49.3°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (48.7°F).

Average pressure in December
Spring Valley, CA

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

The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in December
Spring Valley, CA

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

The windiest month (with the highest average wind speed) is April (5.6mph).
The calmest month (with the lowest average wind speed) is October (4.5mph).

Average humidity in December
Spring Valley, CA

Average humidity in December - Spring Valley, CA
  • Average humidity in December: 59%

The month with the highest relative humidity is May (67%).
The month with the lowest relative humidity is November (54%).

Average rainfall in December
Spring Valley, CA

Average rainfall in December - Spring Valley, CA
  • Average rainfall in December: 0.51"

The wettest month (with the highest rainfall) is February (0.55").
The driest months (with the least rainfall) are June, July and October (0.04").

Average rainfall days in December
Spring Valley, CA

Average rainfall days in December - Spring Valley, CA
  • Average rainfall days in December: 3.5 days

The month with the highest number of rainy days is March (5.3 days).
The month with the least rainy days is June (0.8 days).

Average daylight in December /
Average sunshine in December
Spring Valley, CA

Average daylight in December / Average sunshine in December - Spring Valley, 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 month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 42min).

Average sunshine days in December
Spring Valley, CA

Average sunshine days in December - Spring Valley, CA
  • Average sunshine days in December: 26.7 days

The month with the most sunshine days is October (28.9 days).
The month with the least sunshine days is February (23.4 days).

Average UV index in December
Spring Valley, CA

Average UV index in December - Spring Valley, CA
  • Average UV index in December: 4

The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 4).

Average cloud cover in December
Spring Valley, CA

Average cloud cover in December - Spring Valley, CA
  • Average cloud cover in December: 24

The months with the most cloud cover are March and December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 7).

Average visibility in December
Spring Valley, CA

Average visibility in December - Spring Valley, 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).

Spring Valley, California, USA

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