December weather forecast
Gromore, WA

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Weather in December

The first month of the winter, December, is still a cold month in Gromore, Washington, with an average temperature ranging between max 36.9°F (2.7°C) and min 25.5°F (-3.6°C).

Temperature

December is the coldest month, exhibiting average temperatures of 36.9°F (2.7°C) at the peak and 25.5°F (-3.6°C) at the base.

Humidity

The average relative humidity in December is 80%.

Rainfall

In Gromore, during December, the rain falls for 9.1 days and regularly aggregates up to 0.83" (21mm) of precipitation. Throughout the year, there are 82.2 rainfall days, and 5.43" (138mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through March, September, November and December. December is the month with the most snowfall. Snow falls for 5.4 days and accumulates 2.76" (70mm) 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 7:27 am and sunset at 4:17 pm. On the last day of December, in Gromore, sunrise is at 7:46 am and sunset at 4:25 pm PST.

Sunshine

In December, the average sunshine is 5.9h.

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 estimate of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: During December, 2 as the daily maximum UV index converts into the following advice:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Take to heart! Snow reflection can almost magnify the Sun's UV radiation twofold.
Updated: Jul 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

Gromore's coldest weather arrives in December, when temperatures average a high of 36.9°F (2.7°C) and a low of 25.5°F (-3.6°C).

How cold is it in December?

In Gromore, 36.9°F (2.7°C) is the average high-temperature and 25.5°F (-3.6°C) is the average low-temperature during December.

What is the average humidity in December?

In December, the average relative humidity is 80%.

How many days does it rain in December?

In Gromore, in December, during 9.1 rainfall days, 0.83" (21mm) of precipitation is typically accumulated.

When does it snow the most?

December is the month with the most snowfall. Snow falls for 5.4 days and accumulates 2.76" (70mm) of snow.

How much does it snow in December?

In December, in Gromore, it is snowing for 5.4 days. Throughout December, 2.76" (70mm) of snow is accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 8h and 36min of daylight.

How many hours of daylight does Gromore have in December?

In December, the average day length is 8h and 38min.

When is the sunrise / sunset in December in Gromore?

In December, on the first day of the month, sunrise is at 7:27 am and sunset at 4:17 pm. On the last day of the month, sunrise is at 7:46 am and sunset at 4:25 pm PST.

How long on average sun shines in December?

The average sunshine duration in December is 5.9h.

What is the month with the lowest UV index?

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

What is the UV index reading in December?

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low health threat from 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
Gromore, WA

Average temperature in December - Gromore, WA
  • Average high temperature in December: 36.9°F

The warmest month (with the highest average high temperature) is August (86.5°F).
The month with the lowest average high temperature is December (36.9°F).

  • Average low temperature in December: 25.5°F

The month with the highest average low temperature is August (60.3°F).
The coldest month (with the lowest average low temperature) is December (25.5°F).

Average pressure in December
Gromore, WA

Average pressure in December - Gromore, WA
  • Average pressure in December: 30.14"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
Gromore, WA

Average wind speed in December - Gromore, WA
  • Average wind speed in December: 4.4mph

The windiest month (with the highest average wind speed) is June (7.1mph).
The calmest month (with the lowest average wind speed) is December (4.4mph).

Average humidity in December
Gromore, WA

Average humidity in December - Gromore, WA
  • Average humidity in December: 80%

The month with the highest relative humidity is January (81%).
The months with the lowest relative humidity are July and August (39%).

Average rainfall in December
Gromore, WA

Average rainfall in December - Gromore, WA
  • Average rainfall in December: 0.83"

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

Average rainfall days in December
Gromore, WA

Average rainfall days in December - Gromore, WA
  • Average rainfall days in December: 9.1 days

The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is August (2 days).

Average snowfall in December
Gromore, WA

Average snowfall in December - Gromore, WA
  • Average snowfall in December: 2.76"

The month with the highest snowfall is December (2.76").
The months with the least snowfall are April, May, June, July, August and October (0").

Average snowfall days in December
Gromore, WA

Average snowfall days in December - Gromore, WA
  • Average snowfall days in December: 5.4 days

The month with the highest number of snowfall days is December (5.4 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
Gromore, WA

Average daylight in December / Average sunshine in December - Gromore, WA
  • Average daylight in December: 8h and 4min

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 5min

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 36min).

Average sunshine days in December
Gromore, WA

Average sunshine days in December - Gromore, WA
  • Average sunshine days in December: 17.3 days

The month with the most sunshine days is July (27.5 days).
The month with the least sunshine days is February (15.8 days).

Average UV index in December
Gromore, WA

Average UV index in December - Gromore, WA
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Gromore, WA

Average cloud cover in December - Gromore, WA
  • Average cloud cover in December: 37

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
Gromore, WA

Average visibility in December - Gromore, 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).

Gromore, Washington, USA

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