December weather forecast and climate
Lewistown, MT

Weather in December

December, the first month of the winter, in Lewistown, is also a subzero cold month, with average temperature fluctuating between 29.1°F (-1.6°C) and 16°F (-8.9°C).

Temperature

February and December, with an average high-temperature of 29.1°F (-1.6°C), are the coldest months.

Humidity

In December, the average relative humidity is 77%.

Rainfall

December is the month with the least rainfall in Lewistown. Rain falls for 6 days and accumulates 0.71" (18mm) of precipitation.

Snowfall

January through June, September through December are months with snowfall in Lewistown. In Lewistown, during December, snow falls for 13.5 days and regularly aggregates up to 4.88" (124mm) of snow. Throughout the year, in Lewistown, there are 83.4 snowfall days, and 45.51" (1156mm) of snow is accumulated.

Daylight

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

Sunshine

In December, the average sunshine in Lewistown is 5.6h.

UV index

Months with the lowest UV index are January through April, October through December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from the exposure to the Sun's UV rays for the average person.
Note: The daily maximum UV index of 2 interpret into the following advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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 Lewistown?

The coldest months in Lewistown are February and December, with an average high-temperature of 29.1°F (-1.6°C).

What is the average humidity in December in Lewistown?

In Lewistown, Montana, the average relative humidity in December is 77%.

What is the driest month in Lewistown?

December is the month with the least rainfall in Lewistown, Montana. Rain falls for 6 days and accumulates 0.71" (18mm) of precipitation.

How many days does it rain in December in Lewistown?

In December, the rain falls for 6 days. Throughout December, 0.71" (18mm) of precipitation is accumulated.

How much does it snow in Lewistown in December?

In December, in Lewistown, Montana, it is snowing for 13.5 days. Throughout December, 4.88" (124mm) of snow is accumulated.

What is the month with the shortest days in Lewistown?

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

What is the average length of the day in December in Lewistown?

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

How long on average sun shines in December in Lewistown?

In December, the average sunshine is 5.6h.

What is the month with the lowest UV index in Lewistown?

Months with the lowest UV index in Lewistown are January through April, October through December, with an average maximum UV index of 2.

What is the UV index intensity in December in Lewistown?

In December, the average daily maximum UV index in Lewistown, Montana, is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health from the exposure to the Sun's UV radiation.

Average temperature in December
Lewistown, MT

Average temperature in December - Lewistown, MT
  • Average high temperature in December: 29.1°F

The warmest month (with the highest average high temperature) is July (78.8°F).
Months with the lowest average high temperature are February and December (29.1°F).

  • Average low temperature in December: 16°F

The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).

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Average pressure in December
Lewistown, MT

Average pressure in December - Lewistown, MT
  • Average pressure in December: 30.12"

The month with the highest atmospheric pressure is January (30.13").
The month with the lowest atmospheric pressure is June (29.85").

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Average wind speed in December
Lewistown, MT

Average wind speed in December - Lewistown, MT
  • Average wind speed in December: 9.5mph

The windiest months (with the highest average wind speed) are January, April and October (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).

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Average humidity in December
Lewistown, MT

Average humidity in December - Lewistown, MT
  • Average humidity in December: 77%

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (47%).

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Average rainfall in December
Lewistown, MT

Average rainfall in December - Lewistown, MT
  • Average rainfall in December: 0.71"

The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (0.71").

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Average rainfall days in December
Lewistown, MT

Average rainfall days in December - Lewistown, MT
  • Average rainfall days in December: 6 days

The month with the highest number of rainy days is May (19.3 days).
The month with the least rainy days is January (5.4 days).

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Average snowfall in December
Lewistown, MT

Average snowfall in December - Lewistown, MT
  • Average snowfall in December: 4.88"

The month with the highest snowfall is April (9.13").
Months with the least snowfall are July and August (0").

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Average snowfall days in December
Lewistown, MT

Average snowfall days in December - Lewistown, MT
  • Average snowfall days in December: 13.5 days

The month with the highest number of snowfall days is February (15.2 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
Lewistown, MT

Average daylight in December / Average sunshine in December - Lewistown, 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: 5.6h

The month with the most sunshine is July (Average sunshine: 11.8h).
The month with the least sunshine is February (Average sunshine: 5.5h).

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Average sunshine days in December
Lewistown, MT

Average sunshine days in December - Lewistown, MT
  • Average sunshine days in December: 16 days

The month with the most sunshine days is September (19.3 days).
The month with the least sunshine days is April (8.3 days).

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Average UV index in December
Lewistown, MT

Average UV index in December - Lewistown, MT
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 6).
Months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

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Average cloud cover in December
Lewistown, MT

Average cloud cover in December - Lewistown, MT
  • Average cloud cover in December: 41

The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 16).

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Average visibility in December
Lewistown, MT

Average visibility in December - Lewistown, MT
  • Average visibility in December: 6mi

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

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