December weather forecast
Flagstaff, AZ

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The brown iconic clock tower in the city of Flagstaff, Arizona, with the street signs of Birch Avenue and San Francisco Street
The brown iconic clock tower in the city of Flagstaff, Arizona, with the street signs of Birch Avenue and San Francisco Street

Weather in December

December brings brilliance to winter in Flagstaff with temperatures dropping to an average low of 24.8°F (-4°C) and snowfall reaching its highest at 7.36" (187mm). Despite the chill, the city exhibits a striking winter appeal, attracting tourists. The snow blankets forest trails, mountains, and city landscapes, rendering beautiful snowy scenes. The daylight hours are minimal, marking shorter days. Thus, December symbolizes the peak of winter with a celebration of festivities amidst the snow.

Temperature

Flagstaff experiences its coldest period in January and December, averaging a high-temperature of 42.6°F (5.9°C).

Humidity

The average relative humidity in December is 64%.

Rainfall

In Flagstaff, in December, during 3.6 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. In Flagstaff, during the entire year, the rain falls for 74.8 days and collects up to 12.56" (319mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. The month with the most snowfall is December, when snow falls for 7.4 days and typically aggregates up to 7.36" (187mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 48min of daylight.
On the first day of the month, sunrise is at 7:17 am and sunset at 5:14 pm. On the last day of December, in Flagstaff, sunrise is at 7:34 am and sunset at 5:24 pm MST.

Sunshine

December has the least sunshine of the year in Flagstaff, with an average of 6.8h of sunshine.

UV index

The months with the lowest UV index in Flagstaff are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: In December, the maximum UV index of 2 transforms into these recommendations:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
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Frequently asked questions

What month is the coldest in Flagstaff?

Flagstaff experiences its coldest period in January and December, averaging a high-temperature of 42.6°F (5.9°C).

Is it cold in Flagstaff during December?

The high-temperature, in December, in Flagstaff, is 42.6°F (5.9°C), while the low-temperature averages to 24.8°F (-4°C). In August, the average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, is calculated to be 80.6°F (27°C).

What is the average humidity in December in Flagstaff?

In December, the average relative humidity in Flagstaff is 64%.

How much does it rain in Flagstaff in December?

In Flagstaff, in December, during 3.6 rainfall days, 1.1" (28mm) of precipitation is typically accumulated.

When does it snow the most in Flagstaff?

December is the month with the most snowfall in Flagstaff, Arizona. Snow falls for 7.4 days and accumulates 7.36" (187mm) of snow.

How much does it snow in Flagstaff in December?

In Flagstaff, during December, snow falls for 7.4 days and regularly aggregates up to 7.36" (187mm) of snow.

What is the month with the shortest days in Flagstaff?

The month with the shortest days in Flagstaff, Arizona, is December, with an average of 9h and 48min of daylight.

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

In December, the average day length is 9h and 50min.

When are sunrise and sunset in December in Flagstaff?

On the first day of December in Flagstaff, Arizona, sunrise is at 7:17 am and sunset at 5:14 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 5:24 pm MST.

What is the month with the least sunshine in Flagstaff?

The month with the least sunshine is December, with an average of 6.8h of sunshine.

How many hours of sunshine does Flagstaff have in December?

The average sunshine duration in December in Flagstaff is 6.8h.

When is the lowest UV index in Flagstaff?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Flagstaff.

What is the UV index intensity in December in Flagstaff?

In December, the average daily maximum UV index in Flagstaff is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Flagstaff, AZ

Average temperature in December - Flagstaff, AZ
  • Average high temperature in December: 42.6°F

The warmest month (with the highest average high temperature) is July (82.8°F).
The months with the lowest average high temperature are January and December (42.6°F).

  • Average low temperature in December: 24.8°F

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is December (24.8°F).

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Average pressure in December
Flagstaff, AZ

Average pressure in December - Flagstaff, AZ
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in December
Flagstaff, AZ

Average wind speed in December - Flagstaff, AZ
  • Average wind speed in December: 6.9mph

The windiest month (with the highest average wind speed) is April (9.6mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).

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Average humidity in December
Flagstaff, AZ

Average humidity in December - Flagstaff, AZ
  • Average humidity in December: 64%

The month with the highest relative humidity is January (66%).
The month with the lowest relative humidity is June (24%).

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Average rainfall in December
Flagstaff, AZ

Average rainfall in December - Flagstaff, AZ
  • Average rainfall in December: 1.1"

The wettest month (with the highest rainfall) is July (2.56").
The driest month (with the least rainfall) is June (0.24").

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Average rainfall days in December
Flagstaff, AZ

Average rainfall days in December - Flagstaff, AZ
  • Average rainfall days in December: 3.6 days

The month with the highest number of rainy days is July (16.2 days).
The months with the least rainy days are February and November (2.5 days).

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Average snowfall in December
Flagstaff, AZ

Average snowfall in December - Flagstaff, AZ
  • Average snowfall in December: 7.36"

The month with the highest snowfall is December (7.36").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Flagstaff, AZ

Average snowfall days in December - Flagstaff, AZ
  • Average snowfall days in December: 7.4 days

The month with the highest number of snowfall days is December (7.4 days).
The months with the least snowfall days are June, July and August (0 days).

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Average daylight in December /
Average sunshine in December
Flagstaff, AZ

Average daylight in December / Average sunshine in December - Flagstaff, AZ
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).

  • Average sunshine in December: 6h and 5min

The months with the most sunshine are June and August (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 48min).

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Average sunshine days in December
Flagstaff, AZ

Average sunshine days in December - Flagstaff, AZ
  • Average sunshine days in December: 22.4 days

The month with the most sunshine days is June (25.8 days).
The month with the least sunshine days is July (11.4 days).

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Average UV index in December
Flagstaff, AZ

Average UV index in December - Flagstaff, AZ
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in December
Flagstaff, AZ

Average cloud cover in December - Flagstaff, AZ
  • Average cloud cover in December: 24

The month with the most cloud cover is December (Cloud cover 24).
The month with the least cloud cover is June (Cloud cover 7).

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Average visibility in December
Flagstaff, AZ

Average visibility in December - Flagstaff, AZ
  • 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).

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Flagstaff, Arizona, USA

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