Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
With average high and low temperatures of 34.5°F (1.4°C) and 24.3°F (-4.3°C) respectively, December is Mattawa's coldest month.Humidity
In December, the average relative humidity in Mattawa, Washington, is 81%.Rainfall
The months with the most rainfall in Mattawa are January and December, with an average 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 6.5 days and accumulates 3.43" (87mm) of snow.Daylight
The month with the shortest days in Mattawa is December, with an average of 8h and 36min of daylight.On the first day of December, sunrise is at 7:24 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:44 am and sunset at 4:21 pm PST.
Sunshine
The average sunshine in December is 5.1h.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 of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the ordinary person.Note: The maximum UV index, 2 during December, leads to the following recommendations:
Babies, children, and individuals with sensitive skin should always have protection against extended sun exposure. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Experience reduced UV exposure by about half when donning a wide-brim hat. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
Frequently asked questions
What is the coldest month in Mattawa?
How cold is December in Mattawa?
What is the average humidity in December in Mattawa?
What is the rainiest month in Mattawa?
How much does it rain in Mattawa in December?
When does it snow the most in Mattawa?
How many days does it snow in December in Mattawa?
What is the month with the shortest days in Mattawa?
How many hours of daylight does Mattawa have in December?
What time are sunrise and sunset in December in Mattawa?
How many hours of sunshine does Mattawa have in December?
What are the months with the lowest UV index in Mattawa?
What is the UV index reading in December in Mattawa?
Average temperature in December
Mattawa, WA
- Average high temperature in December: 34.5°F
The warmest months (with the highest average high temperature) are July and August (88.3°F).
The month with the lowest average high temperature is December (34.5°F).
- Average low temperature in December: 24.3°F
The month with the highest average low temperature is August (61.5°F).
The coldest month (with the lowest average low temperature) is December (24.3°F).
Average pressure in December
Mattawa, WA
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in December
Mattawa, WA
- Average wind speed in December: 4.7mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).
Average humidity in December
Mattawa, WA
- Average humidity in December: 81%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is July (37%).
Average rainfall in December
Mattawa, WA
- Average rainfall in December: 0.87"
The wettest months (with the highest rainfall) are January and December (0.87").
The driest month (with the least rainfall) is August (0.2").
Average rainfall days in December
Mattawa, WA
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is August (3.5 days).
Average snowfall in December
Mattawa, WA
- Average snowfall in December: 3.43"
The month with the highest snowfall is December (3.43").
The months with the least snowfall are May, June, July, August and October (0").
Average snowfall days in December
Mattawa, WA
- Average snowfall days in December: 6.5 days
The month with the highest number of snowfall days is December (6.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Mattawa, 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 1min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).
Average sunshine days in December
Mattawa, WA
- Average sunshine days in December: 18.1 days
The months with the most sunshine days are July and August (25.8 days).
The month with the least sunshine days is February (16 days).
Average UV index in December
Mattawa, 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
Mattawa, WA
- Average cloud cover in December: 45
The month with the most cloud cover is January (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 10).
Average visibility in December
Mattawa, WA
- Average visibility in December: 5mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
Mattawa, Washington, USA
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