December weather forecast and climate
Helena, MT

The State Capital building of Montana in Helena city, set on a beautiful natural park
The State Capital building of Montana in Helena city, set on a beautiful natural park

Weather in December

December, the first month of the winter, in Helena, is still a freezing cold month, with average temperature varying between 27.7°F (-2.4°C) and 14.2°F (-9.9°C).

Temperature

The coldest month is December, with an average high-temperature of 27.7°F (-2.4°C) and an average low-temperature of 14.2°F (-9.9°C).

Humidity

In Helena, the average relative humidity is 83%.

Rainfall

January and December are months with the least rain when the rain falls for 7.9 days and typically aggregates up to 0.63" (16mm) of rain.

Snowfall

Months with snowfall in Helena are January through May, September through December. In Helena, during 14.1 snowfall days, 4.61" (117mm) of snow is typically accumulated. In Helena, during the entire year, snow falls for 80.4 days, and aggregates up to 34.88" (886mm) of snow.

Daylight

December has the shortest days of the year in Helena, with an average of 8.6h of daylight.

Sunshine

In December, the average sunshine in Helena is 5.8h.

UV index

In Helena, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 2 in December transform into the following instructions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the coldest month in Helena?

With an average high-temperature of 27.7°F (-2.4°C) and an average low-temperature of 14.2°F (-9.9°C), December is the coldest month.

What is the temperature in December in Helena?

In December, the average high-temperature is 27.7°F (-2.4°C), and the average low-temperature is 14.2°F (-9.9°C).

What is the average humidity in December in Helena?

The average relative humidity in December in Helena is 83%.

How much does it rain in Helena in December?

In Helena, Montana, in December, during 7.9 rainfall days, 0.63" (16mm) of precipitation is typically accumulated.

What is the driest month in Helena?

January and December are months with the least rain when the rain falls for 7.9 days and typically aggregates up to 0.63" (16mm) of rain.

How many days does it snow in December in Helena?

In Helena, in December, during 14.1 snowfall days, 4.61" (117mm) of snow is typically accumulated.

What is the month with the shortest days in Helena?

The month with the shortest days in Helena, Montana, is December, with an average of 8.6h of daylight.

How many hours of daylight does Helena have in December?

In Helena, the average length of the day in December is 8.6h.

How many hours of sunshine does Helena have in December?

The average sunshine in December is 5.8h.

What is the UV index reading in December in Helena?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from unsafe exposure to the Sun's UV rays.

Average temperature in December
Helena, MT

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).

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Average pressure in December
Helena, MT

Average pressure in December - Helena, MT
  • Average pressure in December: 30.17"

The month with the highest atmospheric pressure is January (30.18").
The month with the lowest atmospheric pressure is June (29.9").

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Average wind speed in December
Helena, MT

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).

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Average humidity in December
Helena, MT

Average humidity in December - Helena, MT
  • Average humidity in December: 83%

The month with the highest relative humidity is January (85%).
Months with the lowest relative humidity are July and August (46%).

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Average rainfall in December
Helena, MT

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").

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Average rainfall days in December
Helena, MT

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).

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Average snowfall in December
Helena, MT

Average snowfall in December - Helena, MT
  • Average snowfall in December: 4.61"

The month with the highest snowfall is February (6.18").
Months with the least snowfall are June, July and August (0").

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Average snowfall days in December
Helena, MT

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).
Months with the least snowfall days are July and August (0 days).

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Average daylight in December /
Average sunshine in December
Helena, MT

Average daylight in December / Average sunshine in December - Helena, MT
  • Average daylight in December: 8.6h

The month with the longest days is June (Average daylight: 15.8h).
The month with the shortest days is December (Average daylight: 8.6h).

  • Average sunshine in December: 5.8h

The month with the most sunshine is July (Average sunshine: 11.7h).
The month with the least sunshine is January (Average sunshine: 5.6h).

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Average sunshine days in December
Helena, MT

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).

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Average UV index in December
Helena, MT

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).

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Average cloud cover in December
Helena, MT

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).
Months with the least cloud cover are July and August (Cloud cover 15).

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Average visibility in December
Helena, MT

Average visibility in December - Helena, MT
  • Average visibility in December: 5mi

Months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
Months with the lowest visibility are January, February and December (5mi).

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