December weather forecastBoulder, MT
December
Weather in December
The first month of the winter, December, is also a subzero cold month in Boulder, Montana, with an average temperature fluctuating between 27°F (-2.8°C) and 12.6°F (-10.8°C).Temperature
Boulder experiences its lowest temperatures in December, with an average peak of 27°F (-2.8°C) and a low of 12.6°F (-10.8°C).Humidity
The average relative humidity in December is 84%.Rainfall
December is the month with the least rainfall in Boulder. Rain falls for 8.2 days and accumulates 0.79" (20mm) of precipitation.Snowfall
Months with snowfall in Boulder are January through June, September through December. In December, in Boulder, it is snowing for 16.8 days. Throughout December, 6.22" (158mm) of snow is accumulated. In Boulder, during the entire year, snow falls for 105.8 days and aggregates up to 55.12" (1400mm) of snow.Daylight
With an average of 8h and 42min of daylight, December has the shortest days of the year.On the first day of December in Boulder, sunrise is at 7:51 am and sunset at 4:44 pm. On the last day of the month, sunrise is at 8:11 am and sunset at 4:52 pm MST.
Sunshine
January and December, with an average of 5.6h of sunshine, are months with the least sunshine in Boulder.UV index
The average daily maximum UV index in December in Boulder, Montana, is 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: In December, a daily UV index of 2 turns into the following recommendations:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Boulder, MT
- Average high temperature in December: 27°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (27°F).
- Average low temperature in December: 12.6°F
The month with the highest average low temperature is August (48.6°F).
The coldest month (with the lowest average low temperature) is December (12.6°F).
Average pressure in December
Boulder, MT
- Average pressure in December: 30.18"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Boulder, MT
- Average wind speed in December: 6.4mph
The windiest months (with the highest average wind speed) are January and November (6.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in December
Boulder, MT
- Average humidity in December: 84%
The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is August (46%).
Average rainfall in December
Boulder, MT
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is June (2.68").
The driest month (with the least rainfall) is December (0.79").
Average rainfall days in December
Boulder, MT
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is May (18.2 days).
The month with the least rainy days is November (7.5 days).
Average snowfall in December
Boulder, MT
- Average snowfall in December: 6.22"
The month with the highest snowfall is February (9.72").
The months with the least snowfall are July and August (0").
Average snowfall days in December
Boulder, MT
- Average snowfall days in December: 16.8 days
The month with the highest number of snowfall days is February (18 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in December /
Average sunshine in December
Boulder, MT
- Average daylight in December: 8h and 42min
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 36min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).
Average sunshine days in December
Boulder, MT
- Average sunshine days in December: 13.7 days
The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is February (8.5 days).
Average UV index in December
Boulder, 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
Boulder, MT
- Average cloud cover in December: 44
The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 15).
Average visibility in December
Boulder, 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).
