December weather forecast
Sewickley, PA

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Weather in December

December, the first month of the winter in Sewickley, is also a wintry month, with an average temperature ranging between max 39°F (3.9°C) and min 28°F (-2.2°C).

Temperature

Sewickley experiences a temperature shift at the start of December, with average high-temperatures adjusting from a frosty 48.7°F (9.3°C) in November to a cold 39°F (3.9°C). Throughout December, Sewickley anticipates an average low-temperature of 28°F (-2.2°C).

Humidity

In December, the average relative humidity is 84%.

Rainfall

In Sewickley, in December, it is raining for 10.1 days, with typically 1.57" (40mm) of accumulated precipitation. In Sewickley, during the entire year, the rain falls for 154.8 days and collects up to 21.22" (539mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall in Sewickley. In Sewickley, in December, snow falls for 10.5 days, with typically accumulated 1.69" (43mm) of snow. Throughout the year, in Sewickley, there are 49.9 snowfall days, and 10.12" (257mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 7:25 am and sunset at 4:54 pm. On the last day of December, sunrise is at 7:44 am and sunset at 5:04 pm EST.

Sunshine

The average sunshine in December in Sewickley is 3.2h.

UV index

The month with the lowest UV index in Sewickley, Pennsylvania, is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV rays for the average person.
Note: A typical high UV index of 1 in December suggests the following recommendations:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Experience reduced UV exposure by about half when donning a wide-brim hat. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
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Frequently asked questions

How cold is December in Sewickley?

The average high-temperature and low-temperature during December are 39°F (3.9°C) and 28°F (-2.2°C) respectively. The average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, in August is computed to be 87.8°F (31°C).

What is the average humidity in December in Sewickley?

In Sewickley, Pennsylvania, the average relative humidity in December is 84%.

How much does it rain in Sewickley in December?

In December, in Sewickley, Pennsylvania, the rain falls for 10.1 days. Throughout December, 1.57" (40mm) of precipitation is accumulated.

How many days does it snow in December in Sewickley?

In Sewickley, in December, snow falls for 10.5 days, with typically accumulated 1.69" (43mm) of snow.

What is the month with the shortest days in Sewickley?

With an average of 9h and 18min of daylight, December has the shortest days of the year in Sewickley, Pennsylvania.

How many hours of daylight does Sewickley have in December?

In Sewickley, the average day length in December is 9h and 20min.

What time are sunrise and sunset in December in Sewickley?

On the first day of December, sunrise is at 7:25 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:44 am and sunset at 5:04 pm EST.

How long on average sun shines in December in Sewickley?

In December, the average sunshine duration is 3.2h.

When is the lowest UV index in Sewickley?

December is the month with the lowest UV index in Sewickley, Pennsylvania, with an average maximum UV index of 1.

What is the UV index reading in December in Sewickley?

In December, the average daily maximum UV index in Sewickley, Pennsylvania, is 1. A UV Index reading 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
Sewickley, PA

Average temperature in December - Sewickley, PA
  • Average high temperature in December: 39°F

The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (32.9°F).

  • Average low temperature in December: 28°F

The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (20.3°F).

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Average pressure in December
Sewickley, PA

Average pressure in December - Sewickley, PA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

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Average wind speed in December
Sewickley, PA

Average wind speed in December - Sewickley, PA
  • Average wind speed in December: 7.4mph

The windiest month (with the highest average wind speed) is January (8.1mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

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Average humidity in December
Sewickley, PA

Average humidity in December - Sewickley, PA
  • Average humidity in December: 84%

The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are July and August (75%).

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Average rainfall in December
Sewickley, PA

Average rainfall in December - Sewickley, PA
  • Average rainfall in December: 1.57"

The wettest month (with the highest rainfall) is July (2.36").
The driest month (with the least rainfall) is January (1.22").

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Average rainfall days in December
Sewickley, PA

Average rainfall days in December - Sewickley, PA
  • Average rainfall days in December: 10.1 days

The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (8.1 days).

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Average snowfall in December
Sewickley, PA

Average snowfall in December - Sewickley, PA
  • Average snowfall in December: 1.69"

The month with the highest snowfall is February (2.76").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Sewickley, PA

Average snowfall days in December - Sewickley, PA
  • Average snowfall days in December: 10.5 days

The month with the highest number of snowfall days is January (14.3 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
Sewickley, PA

Average daylight in December / Average sunshine in December - Sewickley, PA
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 3h and 1min

The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 2h and 54min).

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Average sunshine days in December
Sewickley, PA

Average sunshine days in December - Sewickley, PA
  • Average sunshine days in December: 12.9 days

The month with the most sunshine days is November (16.6 days).
The month with the least sunshine days is February (10.7 days).

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Average UV index in December
Sewickley, PA

Average UV index in December - Sewickley, PA
  • Average UV index in December: 1

The months with the highest UV index are May, June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).

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Average cloud cover in December
Sewickley, PA

Average cloud cover in December - Sewickley, PA
  • Average cloud cover in December: 66

The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 34).

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Average visibility in December
Sewickley, PA

Average visibility in December - Sewickley, PA
  • Average visibility in December: 5mi

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

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Sewickley, Pennsylvania, USA

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