December weather forecastDecker, MT
December
Weather in December
December, the first month of the winter in Decker, is also a subzero cold month, with an average temperature ranging between max 31.1°F (-0.5°C) and min 16.7°F (-8.5°C).Temperature
In Decker, the month of December is known for its lowest average temperatures, reaching a high of 31.1°F (-0.5°C) and a low of 16.7°F (-8.5°C).Humidity
In Decker, the average relative humidity in December is 75%.Rainfall
December is the month with the least rainfall in Decker. Rain falls for 6.8 days and accumulates 0.67" (17mm) of precipitation.Snowfall
Months with snowfall are January through May, September through December. In Decker, in December, during 11.2 snowfall days, 3.62" (92mm) of snow is typically accumulated. Throughout the year, there are 65.3 snowfall days, and 28.82" (732mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 8h and 48min of daylight.On the first day of December, sunrise is at 7:26 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:45 am and sunset at 4:36 pm MST.
Sunshine
In Decker, the average sunshine in December is 6.1h.UV index
January through March, 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 hazard from unsafe exposure to UV radiation for the average person.Note: A maximum high daily UV index of 2 during December translates into the following directions:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Decker, MT
- Average high temperature in December: 31.1°F
The warmest month (with the highest average high temperature) is July (85.5°F).
The month with the lowest average high temperature is December (31.1°F).
- Average low temperature in December: 16.7°F
The month with the highest average low temperature is July (61.5°F).
The coldest months (with the lowest average low temperature) are January and February (16.2°F).
Average pressure in December
Decker, MT
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in December
Decker, MT
- Average wind speed in December: 6.8mph
The windiest month (with the highest average wind speed) is April (9.1mph).
The calmest months (with the lowest average wind speed) are July and December (6.8mph).
Average humidity in December
Decker, MT
- Average humidity in December: 75%
The months with the highest relative humidity are January and February (79%).
The month with the lowest relative humidity is August (40%).
Average rainfall in December
Decker, MT
- Average rainfall in December: 0.67"
The wettest month (with the highest rainfall) is May (2.64").
The driest month (with the least rainfall) is December (0.67").
Average rainfall days in December
Decker, MT
- Average rainfall days in December: 6.8 days
The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in December
Decker, MT
- Average snowfall in December: 3.62"
The month with the highest snowfall is February (5.2").
The months with the least snowfall are June, July and August (0").
Average snowfall days in December
Decker, MT
- Average snowfall days in December: 11.2 days
The month with the highest number of snowfall days is February (14.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Decker, MT
- Average daylight in December: 8h and 48min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in December: 6h and 6min
The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 42min).
Average sunshine days in December
Decker, MT
- Average sunshine days in December: 16.5 days
The month with the most sunshine days is September (18.2 days).
The month with the least sunshine days is May (9.6 days).
Average UV index in December
Decker, MT
- 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, March, November and December (UV index 2).
Average cloud cover in December
Decker, MT
- Average cloud cover in December: 37
The month with the most cloud cover is February (Cloud cover 41).
The months with the least cloud cover are July and August (Cloud cover 14).
Average visibility in December
Decker, MT
- 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).
