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
December signals a considerable drop in Westby's average high-temperature, reducing from a cold 36.3°F (2.4°C) in November to a freezing cold 21.9°F (-5.6°C). December witnesses an average nighttime temperature of 10°F (-12.2°C).Humidity
In Westby, the average relative humidity in December is 87%.Rainfall
In Westby, in December, it is raining for 3.6 days, with typically 0.51" (13mm) of accumulated precipitation. In Westby, during the entire year, the rain falls for 93.3 days and collects up to 12.01" (305mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Westby, during December, snow falls for 13 days and regularly aggregates up to 3.19" (81mm) of snow. In Westby, during the entire year, snow falls for 66.5 days and aggregates up to 19.02" (483mm) of snow.Daylight
December has the shortest days of the year in Westby, with an average of 8h and 18min of daylight.On the first day of the month, sunrise is at 8:29 am and sunset at 5:01 pm. On the last day of December, in Westby, sunrise is at 8:49 am and sunset at 5:09 pm CST.
Sunshine
The average sunshine in December in Westby is 4.2h.UV index
In December, the average daily maximum UV index in Westby is 2. A UV Index reading of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 2 in December translates into these instructions:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December in Westby?
What is the average humidity in December in Westby?
How much does it rain in Westby in December?
How much does it snow in Westby in December?
What is the month with the shortest days in Westby?
What is the average length of the day in December in Westby?
When are sunrise and sunset in December in Westby?
How long on average sun shines in December in Westby?
How high is the UV index in December in Westby?
Average temperature in December
Westby, MT
- Average high temperature in December: 21.9°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is February (19.8°F).
- Average low temperature in December: 10°F
The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is February (6.3°F).
Average pressure in December
Westby, MT
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is February (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.83"Hg).
Average wind speed in December
Westby, MT
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is February (9.2mph).
Average humidity in December
Westby, MT
- Average humidity in December: 87%
The months with the highest relative humidity are January and February (88%).
The month with the lowest relative humidity is August (46%).
Average rainfall in December
Westby, MT
- Average rainfall in December: 0.51"
The wettest month (with the highest rainfall) is June (2.17").
The driest month (with the least rainfall) is February (0.47").
Average rainfall days in December
Westby, MT
- Average rainfall days in December: 3.6 days
The month with the highest number of rainy days is June (13.9 days).
The month with the least rainy days is February (2.6 days).
Average snowfall in December
Westby, MT
- Average snowfall in December: 3.19"
The month with the highest snowfall is November (3.74").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Westby, MT
- Average snowfall days in December: 13 days
The month with the highest number of snowfall days is February (13.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Westby, MT
- Average daylight in December: 8h and 2min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 3h and 54min).
Average sunshine days in December
Westby, MT
- Average sunshine days in December: 17.2 days
The month with the most sunshine days is August (20.1 days).
The months with the least sunshine days are February and June (13.8 days).
Average UV index in December
Westby, MT
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in December
Westby, MT
- Average cloud cover in December: 56
The month with the most cloud cover is February (Cloud cover 60).
The months with the least cloud cover are July and August (Cloud cover 19).
Average visibility in December
Westby, MT
- Average visibility in December: 5mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).
Westby, Montana, USA
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