December weather forecast
Round Rock, AZ

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Weather in December

The first month of the winter, December, is also an icy month in Round Rock, Arizona, with an average temperature fluctuating between 25.7°F (-3.5°C) and 40.1°F (4.5°C).

Temperature

Setting in of December comes with a decrease in the average high-temperature, moving from a fresh 52.2°F (11.2°C) in November to a cold 40.1°F (4.5°C). An average nighttime temperature of 25.7°F (-3.5°C) is witnessed in Round Rock throughout December.

Humidity

In December, the average relative humidity in Round Rock is 61%.

Rainfall

In Round Rock, during December, the rain falls for 5.1 days and regularly aggregates up to 0.75" (19mm) of precipitation. Throughout the year, there are 75.5 rainfall days, and 7.91" (201mm) of precipitation is accumulated.

Snowfall

January through May, October through December are months with snowfall in Round Rock. December is the month with the most snowfall. Snow falls for 5.8 days and accumulates 4.8" (122mm) of snow.

Daylight

With an average of 9h and 42min of daylight, December has the shortest days of the year in Round Rock.
On the first day of the month, sunrise is at 7:11 am and sunset at 5:02 pm. On the last day of December, in Round Rock, sunrise is at 7:29 am and sunset at 5:12 pm MST.

Sunshine

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. A UV Index estimate of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: A maximum high UV index of 2 in December translates into the following recommendations:
Despite the majority tolerating prolonged sun exposure, those with sensitive skin, infants, and children demand continual protection. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
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Frequently asked questions

Is it cold in Round Rock during December?

During December, Round Rock experiences an average high-temperature of 40.1°F (4.5°C) and a low-temperature of 25.7°F (-3.5°C).

What is the average humidity in December in Round Rock?

In Round Rock, the average relative humidity in December is 61%.

How many days does it rain in December in Round Rock?

In Round Rock, during December, the rain falls for 5.1 days and regularly aggregates up to 0.75" (19mm) of precipitation.

When does it snow the most in Round Rock?

The month with the most snowfall in Round Rock is December, when snow falls for 5.8 days and typically aggregates up to 4.8" (122mm) of snow.

How much does it snow in Round Rock in December?

In December, in Round Rock, it is snowing for 5.8 days. Throughout December, 4.8" (122mm) of snow is accumulated.

What is the month with the shortest days in Round Rock?

With an average of 9h and 42min of daylight, December has the shortest days of the year in Round Rock.

How many hours of daylight does Round Rock have in December?

The average day length in December is 9h and 43min.

What time are sunrise and sunset in December in Round Rock?

On the first day of December in Round Rock, Arizona, sunrise is at 7:11 am and sunset at 5:02 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 5:12 pm MST.

How many hours of sunshine does Round Rock have in December?

The average sunshine duration in December in Round Rock is 6.8h.

What are the months with the lowest UV index in Round Rock?

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

How high is the UV index in December in Round Rock?

In December, the average daily maximum UV index is 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to UV radiation.
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
Round Rock, AZ

Average temperature in December - Round Rock, AZ
  • Average high temperature in December: 40.1°F

The warmest month (with the highest average high temperature) is July (86.9°F).
The month with the lowest average high temperature is January (38.8°F).

  • Average low temperature in December: 25.7°F

The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).

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Average pressure in December
Round Rock, AZ

Average pressure in December - Round Rock, AZ
  • Average pressure in December: 30.14"Hg

The month with the highest atmospheric pressure is January (30.2"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

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Average wind speed in December
Round Rock, AZ

Average wind speed in December - Round Rock, AZ
  • Average wind speed in December: 6mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is January (5.5mph).

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Average humidity in December
Round Rock, AZ

Average humidity in December - Round Rock, AZ
  • Average humidity in December: 61%

The month with the highest relative humidity is January (67%).
The month with the lowest relative humidity is June (19%).

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Average rainfall in December
Round Rock, AZ

Average rainfall in December - Round Rock, AZ
  • Average rainfall in December: 0.75"

The wettest month (with the highest rainfall) is July (1.3").
The driest month (with the least rainfall) is June (0.2").

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Average rainfall days in December
Round Rock, AZ

Average rainfall days in December - Round Rock, AZ
  • Average rainfall days in December: 5.1 days

The month with the highest number of rainy days is July (13.7 days).
The months with the least rainy days are February and June (3.3 days).

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Average snowfall in December
Round Rock, AZ

Average snowfall in December - Round Rock, AZ
  • Average snowfall in December: 4.8"

The month with the highest snowfall is December (4.8").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Round Rock, AZ

Average snowfall days in December - Round Rock, AZ
  • Average snowfall days in December: 5.8 days

The months with the highest number of snowfall days are January and December (5.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in December /
Average sunshine in December
Round Rock, AZ

Average daylight in December / Average sunshine in December - Round Rock, AZ
  • Average daylight in December: 9h and 4min

The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in December: 6h and 5min

The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 6h and 42min).

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Average sunshine days in December
Round Rock, AZ

Average sunshine days in December - Round Rock, AZ
  • Average sunshine days in December: 21.7 days

The month with the most sunshine days is June (25.4 days).
The month with the least sunshine days is July (13.2 days).

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Average UV index in December
Round Rock, AZ

Average UV index in December - Round Rock, AZ
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 7).
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
Round Rock, AZ

Average cloud cover in December - Round Rock, AZ
  • Average cloud cover in December: 24

The months with the most cloud cover are January and December (Cloud cover 24).
The month with the least cloud cover is June (Cloud cover 9).

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Average visibility in December
Round Rock, AZ

Average visibility in December - Round Rock, 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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Round Rock, Arizona, USA

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