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
Welcoming December, Joliett observes a shift in the average high-temperature, falling from November's chilly 48.7°F (9.3°C) to a cold 39.7°F (4.3°C). During the December nights, an average temperature of 28.2°F (-2.1°C) is observed.Humidity
In December, the average relative humidity is 81%.Rainfall
In Joliett, in December, it is raining for 9.5 days, with typically 1.02" (26mm) of accumulated precipitation. Throughout the year, in Joliett, there are 133.5 rainfall days, and 15.16" (385mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. In Joliett, in December, snow falls for 3.9 days, with typically accumulated 0.91" (23mm) of snow. Throughout the year, in Joliett, Pennsylvania, there are 23.2 snowfall days, and 5.67" (144mm) 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 December, sunrise is at 7:10 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 4:48 pm EST.
Sunshine
The average sunshine in December in Joliett is 4.4h.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 radiation for average individuals.Note: In December, the maximum UV index of 2 translates into these guidelines:
In contrast to children, who must always be shielded from the sun, most people can tolerate up to an hour of sun exposure without any burns. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. During bright days, sunglasses that offer UVA and UVB defense are recommended. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
How many days does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Joliett, PA
- Average high temperature in December: 39.7°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 (33.4°F).
- Average low temperature in December: 28.2°F
The month with the highest average low temperature is July (62.1°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).
Average pressure in December
Joliett, 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
Joliett, PA
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in December
Joliett, PA
- Average humidity in December: 81%
The month with the highest relative humidity is February (82%).
The months with the lowest relative humidity are March and April (77%).
Average rainfall in December
Joliett, PA
- Average rainfall in December: 1.02"
The wettest month (with the highest rainfall) is August (1.93").
The driest month (with the least rainfall) is February (0.83").
Average rainfall days in December
Joliett, PA
- Average rainfall days in December: 9.5 days
The month with the highest number of rainy days is May (15.4 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in December
Joliett, PA
- Average snowfall in December: 0.91"
The month with the highest snowfall is January (1.77").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Joliett, PA
- Average snowfall days in December: 3.9 days
The month with the highest number of snowfall days is January (6.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Joliett, 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 12min).
The month with the least sunshine is February (Average sunshine: 4h and 18min).
Average sunshine days in December
Joliett, PA
- Average sunshine days in December: 18.3 days
The month with the most sunshine days is January (20.8 days).
The month with the least sunshine days is May (12.7 days).
Average UV index in December
Joliett, PA
- Average UV index in December: 2
The months with the highest UV index are June and 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
Joliett, PA
- Average cloud cover in December: 53
The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is July (Cloud cover 33).
Average visibility in December
Joliett, PA
- Average visibility in December: 6mi
The months with the highest visibility are January, March, April, June, November and December (6mi).
The months with the lowest visibility are February, May, July, August, September and October (5mi).
Joliett, Pennsylvania, USA
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