December weather forecastPomona, WA

December

Weather in December

December, the first month of the winter in Pomona, is also an icy month, with temperature in the range of an average high of 36°F (2.2°C) and an average low of 23.9°F (-4.5°C).

Temperature

Pomona experiences its lowest average temperatures in December, reaching a peak of 36°F (2.2°C) and a minimum of 23.9°F (-4.5°C).

Humidity

In December, the average relative humidity is 82%.

Rainfall

The month with the most rainfall is December, when the rain falls for 9.2 days and typically aggregates up to 0.87" (22mm) of precipitation.

Snowfall

Months with snowfall are January through April, September, November and December. December is the month with the most snowfall. Snow falls for 5.7 days and accumulates 3.07" (78mm) of snow.

Daylight

The month with the shortest days is December, with an average of 8h and 36min of daylight.
On the first day of the month, sunrise is at 7:26 am and sunset at 4:15 pm. On the last day of December, sunrise is at 7:46 am and sunset at 4:24 pm PST.

Sunshine

In December, the average sunshine is 5.8h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 2 transforms into these recommendations:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. 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. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.

Frequently asked questions

Pomona witnesses the coldest weather in December, with temperatures averaging a high of 36°F (2.2°C) and a low of 23.9°F (-4.5°C).

The average high-temperature, in December, in Pomona, is 36°F (2.2°C), while the average low-temperature is 23.9°F (-4.5°C). In August, the average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, is evaluated at 84.2°F (29°C).

The average relative humidity in December is 82%.

The month with the most rainfall is December, when the rain falls for 9.2 days and typically aggregates up to 0.87" (22mm) of precipitation.

In December, the rain falls for 9.2 days. Throughout December, 0.87" (22mm) of precipitation is accumulated.

December is the month with the most snowfall. Snow falls for 5.7 days and accumulates 3.07" (78mm) of snow.

In Pomona, in December, during 5.7 snowfall days, 3.07" (78mm) of snow is typically accumulated.

December has the shortest days of the year, with an average of 8h and 36min of daylight.

The average day length in December is 8h and 38min.

On the first day of December, sunrise is at 7:26 am and sunset at 4:15 pm. On the last day of the month, sunrise is at 7:46 am and sunset at 4:24 pm PST.

In Pomona, the average sunshine duration in December is 5.8h.

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health threat from exposure to the Sun's 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
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Pomona, WA

  • Average high temperature in December: 36°F

The warmest month (with the highest average high temperature) is August (85.1°F).
The month with the lowest average high temperature is December (36°F).

  • Average low temperature in December: 23.9°F

The month with the highest average low temperature is August (58.8°F).
The coldest month (with the lowest average low temperature) is December (23.9°F).

Average pressure in December
Pomona, WA

  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.93"Hg).

Average wind speed in December
Pomona, WA

  • Average wind speed in December: 4.2mph

The windiest month (with the highest average wind speed) is June (7.4mph).
The calmest month (with the lowest average wind speed) is December (4.2mph).

Average humidity in December
Pomona, WA

  • Average humidity in December: 82%

The month with the highest relative humidity is January (83%).
The months with the lowest relative humidity are July and August (41%).

Average rainfall in December
Pomona, WA

  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is December (0.87").
The driest month (with the least rainfall) is July (0.08").

Average rainfall days in December
Pomona, WA

  • Average rainfall days in December: 9.2 days

The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is July (2.3 days).

Average snowfall in December
Pomona, WA

  • Average snowfall in December: 3.07"

The month with the highest snowfall is December (3.07").
The months with the least snowfall are May, June, July, August and October (0").

Average snowfall days in December
Pomona, WA

  • Average snowfall days in December: 5.7 days

The month with the highest number of snowfall days is December (5.7 days).
The months with the least snowfall days are May, June, July, August and October (0 days).

Average daylight in December /
Average sunshine in December
Pomona, WA

  • Average daylight in December: 8h and 36min

The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).

  • Average sunshine in December: 5h and 48min

The months with the most sunshine are July and August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 30min).

Average sunshine days in December
Pomona, WA

  • Average sunshine days in December: 17.9 days

The month with the most sunshine days is July (27.6 days).
The month with the least sunshine days is February (15.5 days).

Average UV index in December
Pomona, WA

  • Average UV index in December: 2

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Pomona, WA

  • Average cloud cover in December: 38

The month with the most cloud cover is January (Cloud cover 40).
The months with the least cloud cover are July and August (Cloud cover 9).

Average visibility in December
Pomona, WA

  • Average visibility in December: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).