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
The coldest month is December, with an average high-temperature of 38.7°F (3.7°C) and an average low-temperature of 28.6°F (-1.9°C).Humidity
The average relative humidity in December is 77%.Rainfall
In Umatilla, in December, it is raining for 11.5 days, with typically 0.98" (25mm) of accumulated precipitation. Throughout the year, in Umatilla, there are 106.1 rainfall days, and 7.76" (197mm) of precipitation is accumulated.Snowfall
January through March, September, November and December are months with snowfall. In Umatilla, in December, snow falls for 3.2 days, with typically accumulated 1.22" (31mm) of snow. Throughout the year, there are 10.3 snowfall days, and 6.02" (153mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 8h and 42min of daylight.On the first day of December, sunrise is at 7:19 am and sunset at 4:14 pm. On the last day of the month, sunrise is at 7:38 am and sunset at 4:22 pm PST.
Sunshine
The months with the least sunshine are January and December, with an average of 5.4h of sunshine.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 vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: In December, the maximum UV index of 2 suggests this advice:
Most individuals face no significant issues with extended sun exposure, but it is always essential to protect children, babies, and those with sensitive skin. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month in Umatilla?
How cold does it get in December?
What is the average humidity in December?
How many days does it rain in December?
How much does it snow in December?
What is the month with the shortest days in Umatilla?
What is the average length of the day in December?
What time are sunrise and sunset in December?
What are the months with the least sunshine?
How many hours of sunshine does Umatilla have in December?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Umatilla, OR
- Average high temperature in December: 38.7°F
The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is December (38.7°F).
- Average low temperature in December: 28.6°F
The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is December (28.6°F).
Average pressure in December
Umatilla, OR
- Average pressure in December: 30.16"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in December
Umatilla, OR
- Average wind speed in December: 6.2mph
The windiest month (with the highest average wind speed) is April (9.3mph).
The calmest month (with the lowest average wind speed) is December (6.2mph).
Average humidity in December
Umatilla, OR
- Average humidity in December: 77%
The month with the highest relative humidity is January (79%).
The months with the lowest relative humidity are July and August (36%).
Average rainfall in December
Umatilla, OR
- Average rainfall in December: 0.98"
The wettest month (with the highest rainfall) is March (1.02").
The driest month (with the least rainfall) is July (0.16").
Average rainfall days in December
Umatilla, OR
- Average rainfall days in December: 11.5 days
The month with the highest number of rainy days is March (13.1 days).
The month with the least rainy days is July (3.8 days).
Average snowfall in December
Umatilla, OR
- Average snowfall in December: 1.22"
The month with the highest snowfall is February (2.83").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in December
Umatilla, OR
- Average snowfall days in December: 3.2 days
The month with the highest number of snowfall days is December (3.2 days).
The months with the least snowfall days are April, May, June, July, August and October (0 days).
Average daylight in December /
Average sunshine in December
Umatilla, OR
- Average daylight in December: 8h and 4min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in December: 5h and 2min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 5h and 24min).
Average sunshine days in December
Umatilla, OR
- Average sunshine days in December: 15.8 days
The month with the most sunshine days is July (25.3 days).
The month with the least sunshine days is February (14 days).
Average UV index in December
Umatilla, OR
- 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
Umatilla, OR
- Average cloud cover in December: 44
The months with the most cloud cover are January and December (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in December
Umatilla, OR
- 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).
Umatilla, Oregon, USA
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