December weather forecast
Glassport, PA

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Weather in December

December, the first month of the winter in Glassport, is also an icy month, with an average temperature fluctuating between 39.6°F (4.2°C) and 28.4°F (-2°C).

Temperature

Glassport's average high-temperature decreases in December, falling from a chilly 49.3°F (9.6°C) in November to an icy 39.6°F (4.2°C). Glassport experiences a mean low-temperature of 28.4°F (-2°C) during December.

Humidity

The average relative humidity in December in Glassport is 83%.

Rainfall

In December, in Glassport, the rain falls for 8.5 days. Throughout December, 0.79" (20mm) of precipitation is accumulated. In Glassport, during the entire year, the rain falls for 128 days and collects up to 10.2" (259mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Glassport, in December, during 10.1 snowfall days, 1.26" (32mm) of snow is typically accumulated. In Glassport, during the entire year, snow falls for 50 days and aggregates up to 6.69" (170mm) of snow.

Daylight

With an average of 9h and 24min 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 4:53 pm. On the last day of December, sunrise is at 7:42 am and sunset at 5:03 pm EST.

Sunshine

The average sunshine in December is 3.4h.

UV index

With an average maximum UV index of 1, December is the month with the lowest UV index. A UV Index value of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the average person.
Note: The UV index of 1 during December translates into the following guidance:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.

Frequently asked questions

How cold is it in December?

December temperatures vary between a high-temperature of 39.6°F (4.2°C) and a low-temperature of 28.4°F (-2°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in August is computed to be 87.8°F (31°C).

What is the average humidity in December?

In December, the average relative humidity is 83%.

How much does it rain in Glassport in December?

In Glassport, in December, it is raining for 8.5 days, with typically 0.79" (20mm) of accumulated precipitation.

How many days does it snow in December?

In Glassport, during December, snow falls for 10.1 days and regularly aggregates up to 1.26" (32mm) of snow.

What is the month with the shortest days?

The month with the shortest days in Glassport, Pennsylvania, is December, with an average of 9h and 24min of daylight.

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

In Glassport, the average day length in December is 9h and 21min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:23 am and sunset at 4:53 pm. On the last day of the month, sunrise is at 7:42 am and sunset at 5:03 pm EST.

How many hours of sunshine does Glassport have in December?

In Glassport, the average sunshine duration in December is 3.4h.

What is the month with the lowest UV index?

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

What is the UV index reading in December?

In Glassport, the average daily maximum UV index in December is 1. A UV Index reading of 2, and below, represents a low health risk from unsafe 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
Glassport, PA

Average temperature in December - Glassport, PA
  • Average high temperature in December: 39.6°F

The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (33.4°F).

  • Average low temperature in December: 28.4°F

The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).

Average pressure in December
Glassport, PA

Average pressure in December - Glassport, 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).

Average wind speed in December
Glassport, PA

Average wind speed in December - Glassport, PA
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is January (8mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

Average humidity in December
Glassport, PA

Average humidity in December - Glassport, PA
  • Average humidity in December: 83%

The month with the highest relative humidity is February (85%).
The month with the lowest relative humidity is August (74%).

Average rainfall in December
Glassport, PA

Average rainfall in December - Glassport, PA
  • Average rainfall in December: 0.79"

The wettest month (with the highest rainfall) is May (1.26").
The driest months (with the least rainfall) are September and November (0.55").

Average rainfall days in December
Glassport, PA

Average rainfall days in December - Glassport, PA
  • Average rainfall days in December: 8.5 days

The month with the highest number of rainy days is May (15 days).
The month with the least rainy days is February (7.1 days).

Average snowfall in December
Glassport, PA

Average snowfall in December - Glassport, PA
  • Average snowfall in December: 1.26"

The months with the highest snowfall are January and February (1.65").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Glassport, PA

Average snowfall days in December - Glassport, PA
  • Average snowfall days in December: 10.1 days

The month with the highest number of snowfall days is January (14.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Glassport, 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 24min).

  • Average sunshine in December: 3h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

Average sunshine days in December
Glassport, PA

Average sunshine days in December - Glassport, PA
  • Average sunshine days in December: 16.5 days

The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is May (12.3 days).

Average UV index in December
Glassport, PA

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

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

Average cloud cover in December
Glassport, PA

Average cloud cover in December - Glassport, PA
  • Average cloud cover in December: 65

The month with the most cloud cover is January (Cloud cover 69).
The month with the least cloud cover is August (Cloud cover 33).

Average visibility in December
Glassport, PA

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

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

Glassport, Pennsylvania, USA

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