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 lowest temperatures in Boulder are recorded in December, with averages reaching a high of 35.2°F (1.8°C) and a low of 18.1°F (-7.7°C).Humidity
The average relative humidity in December is 65%.Rainfall
In Boulder, in December, it is raining for 3.9 days, with typically 0.51" (13mm) of accumulated precipitation. In Boulder, Colorado, during the entire year, the rain falls for 117.3 days and collects up to 14.17" (360mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Boulder, in December, snow falls for 7.2 days, with typically accumulated 3.94" (100mm) of snow. Throughout the year, in Boulder, there are 44.8 snowfall days, and 37.01" (940mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 7:04 am and sunset at 4:36 pm. On the last day of December, in Boulder, Colorado, sunrise is at 7:22 am and sunset at 4:46 pm MST.
Sunshine
In Boulder, Colorado, the average sunshine in December is 6.8h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Boulder. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for the average person.Note: A typical high UV index of 2 in December suggests the following recommendations:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Frequently asked questions
What is the coldest time of year in Boulder?
How cold is December in Boulder?
What is the average humidity in December in Boulder?
How many days does it rain in December in Boulder?
How many days does it snow in December in Boulder?
What is the month with the shortest days in Boulder?
How many hours of daylight does Boulder have in December?
What time are sunrise and sunset in December in Boulder?
How long on average sun shines in December in Boulder?
What are the months with the lowest UV index in Boulder?
What is the UV index intensity in December in Boulder?
Average temperature in December
Boulder, CO
- Average high temperature in December: 35.2°F
The warmest month (with the highest average high temperature) is July (80.4°F).
The month with the lowest average high temperature is December (35.2°F).
- Average low temperature in December: 18.1°F
The month with the highest average low temperature is July (55.2°F).
The coldest month (with the lowest average low temperature) is February (18°F).
Average pressure in December
Boulder, CO
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are April, May and June (29.92"Hg).
Average wind speed in December
Boulder, CO
- Average wind speed in December: 6.8mph
The windiest month (with the highest average wind speed) is January (7.3mph).
The calmest months (with the lowest average wind speed) are May, July, August and September (5.7mph).
Average humidity in December
Boulder, CO
- Average humidity in December: 65%
The month with the highest relative humidity is February (70%).
The months with the lowest relative humidity are June, August and September (45%).
Average rainfall in December
Boulder, CO
- Average rainfall in December: 0.51"
The wettest month (with the highest rainfall) is May (2.48").
The driest month (with the least rainfall) is January (0.39").
Average rainfall days in December
Boulder, CO
- Average rainfall days in December: 3.9 days
The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is November (3.3 days).
Average snowfall in December
Boulder, CO
- Average snowfall in December: 3.94"
The month with the highest snowfall is April (7.76").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Boulder, CO
- Average snowfall days in December: 7.2 days
The month with the highest number of snowfall days is February (10.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Boulder, CO
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 6h and 5min
The months with the most sunshine are June and July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 36min).
Average sunshine days in December
Boulder, CO
- Average sunshine days in December: 21.9 days
The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in December
Boulder, CO
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Boulder, CO
- Average cloud cover in December: 24
The months with the most cloud cover are April and May (Cloud cover 28).
The month with the least cloud cover is September (Cloud cover 16).
Average visibility in December
Boulder, CO
- 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).
Boulder, Colorado, USA
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