Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
As December commences, the average high-temperature shows a reduction, transitioning from a chilly 48°F (8.9°C) in November to a cold 38.8°F (3.8°C). The temperature in Saint Clair, Pennsylvania, dips to an average of 27.7°F (-2.4°C) during December nights.Humidity
In Saint Clair, Pennsylvania, the average relative humidity in December is 81%.Rainfall
In December, the rain falls for 13.5 days. Throughout December, 2.87" (73mm) of precipitation is accumulated. In Saint Clair, during the entire year, the rain falls for 172.9 days and collects up to 34.21" (869mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Saint Clair, during December, snow falls for 6.9 days and regularly aggregates up to 2.8" (71mm) of snow. Throughout the year, in Saint Clair, there are 39.7 snowfall days, and 20.47" (520mm) 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 7:10 am and sunset at 4:38 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:47 pm EST.
Sunshine
January, February and December, with an average of 4.4h of sunshine, are months with the least sunshine in Saint Clair.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for the average person.Note: A maximum UV index of 2 in December translates into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties of snow.
Frequently asked questions
How cold is it in Saint Clair in December?
What is the average humidity in December in Saint Clair?
How many days does it rain in December in Saint Clair?
How many days does it snow in December in Saint Clair?
What is the month with the shortest days in Saint Clair?
How many hours of daylight does Saint Clair have in December?
When is the sunrise / sunset in December in Saint Clair?
What is the month with the least sunshine in Saint Clair?
How many hours of sunshine does Saint Clair have in December?
What is the month with the lowest UV index in Saint Clair?
What is the UV index intensity in December in Saint Clair?
Average temperature in December
Saint Clair, PA
- Average high temperature in December: 38.8°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (32.5°F).
- Average low temperature in December: 27.7°F
The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in December
Saint Clair, PA
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Saint Clair, PA
- Average wind speed in December: 7.7mph
The windiest month (with the highest average wind speed) is March (8.4mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in December
Saint Clair, PA
- Average humidity in December: 81%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is April (77%).
Average rainfall in December
Saint Clair, PA
- Average rainfall in December: 2.87"
The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is September (2.09").
Average rainfall days in December
Saint Clair, PA
- Average rainfall days in December: 13.5 days
The month with the highest number of rainy days is May (18.7 days).
The months with the least rainy days are January and November (10.8 days).
Average snowfall in December
Saint Clair, PA
- Average snowfall in December: 2.8"
The month with the highest snowfall is January (5.47").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Saint Clair, PA
- Average snowfall days in December: 6.9 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Saint Clair, 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: 4h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The months with the least sunshine are January, February and December (Average sunshine: 4h and 24min).
Average sunshine days in December
Saint Clair, PA
- Average sunshine days in December: 14.2 days
The month with the most sunshine days is November (16.3 days).
The month with the least sunshine days is May (9.6 days).
Average UV index in December
Saint Clair, PA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in December
Saint Clair, PA
- Average cloud cover in December: 53
The months with the most cloud cover are February and December (Cloud cover 53).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in December
Saint Clair, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).
Saint Clair, Pennsylvania, USA
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