December weather forecast
Summerville, PA

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Weather in December

December, the first month of the winter in Summerville, is also an icy month, with an average temperature fluctuating between 36.5°F (2.5°C) and 25.5°F (-3.6°C).

Temperature

December brings a drop in Summerville's average high-temperature, falling from a frosty 45.7°F (7.6°C) in November to a cold 36.5°F (2.5°C). In Summerville, the average temperature during the nights of December drops to a subzero cold 25.5°F (-3.6°C).

Humidity

The average relative humidity in December is 86%.

Rainfall

In December, the rain falls for 10.2 days. Throughout December, 1.61" (41mm) of precipitation is accumulated. In Summerville, during the entire year, the rain falls for 150.5 days and collects up to 22.05" (560mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Summerville, during December, snow falls for 13.5 days and regularly aggregates up to 3.74" (95mm) of snow. Throughout the year, there are 72.4 snowfall days, and 22.28" (566mm) of snow is accumulated.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:23 am and sunset at 4:48 pm. On the last day of December, sunrise is at 7:41 am and sunset at 4:58 pm EST.

Sunshine

In December, the average sunshine is 2.7h.

UV index

The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, the maximum UV index of 1 transforms into these recommendations:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.

Frequently asked questions

How cold is December?

In December, the average high-temperature and low-temperature are 36.5°F (2.5°C) and 25.5°F (-3.6°C) respectively. In July, the average heat index (a.k.a. 'real feel', 'feels like'), which factors the actual air temperature with the relative humidity, is computed to be 86°F (30°C).

What is the average humidity in December in Summerville?

In December, the average relative humidity is 86%.

How much does it rain in December?

In Summerville, in December, it is raining for 10.2 days, with typically 1.61" (41mm) of accumulated precipitation.

How many days does it snow in December?

In Summerville, in December, snow falls for 13.5 days, with typically accumulated 3.74" (95mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

What is the average length of the day in December?

In Summerville, the average day length in December is 9h and 16min.

What time are sunrise and sunset in December?

On the first day of December, sunrise is at 7:23 am and sunset at 4:48 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 4:58 pm EST.

How many hours of sunshine does Summerville have in December?

In December, the average sunshine duration is 2.7h.

What is the month with the lowest UV index?

With an average maximum UV index of 1, December is the month with the lowest UV index.

How high is the UV index in December?

The average daily maximum UV index in December is 1. A UV Index reading of 2, and below, represents a low health threat 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
Summerville, PA

Average temperature in December - Summerville, PA
  • Average high temperature in December: 36.5°F

The warmest month (with the highest average high temperature) is July (80.6°F).
The month with the lowest average high temperature is January (30.2°F).

  • Average low temperature in December: 25.5°F

The month with the highest average low temperature is July (58.8°F).
The coldest month (with the lowest average low temperature) is January (17.8°F).

Average pressure in December
Summerville, PA

Average pressure in December - Summerville, PA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Summerville, PA

Average wind speed in December - Summerville, PA
  • Average wind speed in December: 8.3mph

The windiest month (with the highest average wind speed) is January (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).

Average humidity in December
Summerville, PA

Average humidity in December - Summerville, PA
  • Average humidity in December: 86%

The month with the highest relative humidity is February (88%).
The months with the lowest relative humidity are June, July and August (78%).

Average rainfall in December
Summerville, PA

Average rainfall in December - Summerville, PA
  • Average rainfall in December: 1.61"

The wettest month (with the highest rainfall) is April (2.56").
The driest month (with the least rainfall) is November (1.26").

Average rainfall days in December
Summerville, PA

Average rainfall days in December - Summerville, PA
  • Average rainfall days in December: 10.2 days

The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (7.2 days).

Average snowfall in December
Summerville, PA

Average snowfall in December - Summerville, PA
  • Average snowfall in December: 3.74"

The month with the highest snowfall is February (5.51").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Summerville, PA

Average snowfall days in December - Summerville, PA
  • Average snowfall days in December: 13.5 days

The month with the highest number of snowfall days is January (18 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Summerville, PA

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

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 2h and 4min

The months with the most sunshine are July and August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 2h and 30min).

Average sunshine days in December
Summerville, PA

Average sunshine days in December - Summerville, PA
  • Average sunshine days in December: 11.4 days

The month with the most sunshine days is November (15.3 days).
The month with the least sunshine days is February (8.1 days).

Average UV index in December
Summerville, PA

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

The months with the highest UV index are May, June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in December
Summerville, PA

Average cloud cover in December - Summerville, PA
  • Average cloud cover in December: 72

The month with the most cloud cover is January (Cloud cover 76).
The months with the least cloud cover are July and August (Cloud cover 39).

Average visibility in December
Summerville, PA

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

The month with the highest visibility is April (6mi).
The month with the lowest visibility is February (4mi).

Summerville, Pennsylvania, USA

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