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 temperatures occur during December, when averages reach a peak of 27.7°F (-2.4°C) and a low of 14.2°F (-9.9°C).Humidity
The average relative humidity in December in Helena is 83%.Rainfall
January and December are months with the least rain in Helena when the rain falls for 7.9 days and typically aggregates up to 0.63" (16mm) of rain.Snowfall
January through May, September through December are months with snowfall in Helena. In Helena, Montana, in December, snow falls for 14.1 days, with typically accumulated 4.61" (117mm) of snow. Throughout the year, in Helena, there are 80.4 snowfall days, and 34.88" (886mm) of snow is accumulated.Daylight
The month with the shortest days in Helena is December, with an average of 8h and 36min of daylight.On the first day of December in Helena, sunrise is at 7:52 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 8:12 am and sunset at 4:50 pm MST.
Sunshine
In Helena, Montana, the average sunshine in December is 5.8h.UV index
In December, the average daily maximum UV index in Helena, Montana, is 2. A UV Index value of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for average individuals.Note: The maximum daily UV index of 2 during December translates into the following directions:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Direct Sun exposure should be minimized especially during midday when radiation is most intense. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month in Helena?
How cold is it in Helena in December?
What is the average humidity in December in Helena?
What is the driest month in Helena?
How much does it rain in Helena in December?
How much does it snow in Helena in December?
What is the month with the shortest days in Helena?
How many hours of daylight does Helena have in December?
When is the sunrise / sunset in December in Helena?
How long on average sun shines in December in Helena?
What is the UV index intensity in December in Helena?
Average temperature in December
Helena, MT
- Average high temperature in December: 27.7°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (27.7°F).
- Average low temperature in December: 14.2°F
The month with the highest average low temperature is July (50.4°F).
The coldest month (with the lowest average low temperature) is December (14.2°F).
Average pressure in December
Helena, MT
- Average pressure in December: 30.17"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Helena, MT
- Average wind speed in December: 6.8mph
The windiest month (with the highest average wind speed) is November (7.1mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in December
Helena, MT
- Average humidity in December: 83%
The month with the highest relative humidity is January (85%).
The months with the lowest relative humidity are July and August (46%).
Average rainfall in December
Helena, MT
- Average rainfall in December: 0.63"
The wettest month (with the highest rainfall) is June (2.01").
The driest months (with the least rainfall) are January and December (0.63").
Average rainfall days in December
Helena, MT
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is May (15.8 days).
The month with the least rainy days is November (7 days).
Average snowfall in December
Helena, MT
- Average snowfall in December: 4.61"
The month with the highest snowfall is February (6.18").
The months with the least snowfall are June, July and August (0").
Average snowfall days in December
Helena, MT
- Average snowfall days in December: 14.1 days
The month with the highest number of snowfall days is February (16.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in December /
Average sunshine in December
Helena, MT
- Average daylight in December: 8h and 4min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in December: 5h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 5h and 36min).
Average sunshine days in December
Helena, MT
- Average sunshine days in December: 15.5 days
The month with the most sunshine days is July (20.5 days).
The month with the least sunshine days is April (9.8 days).
Average UV index in December
Helena, 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
Helena, MT
- Average cloud cover in December: 43
The month with the most cloud cover is February (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in December
Helena, MT
- Average visibility in December: 5mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
Helena, Montana, USA
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