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
December brings a drop in Saint Johns's average high-temperature, falling from a frosty 46.9°F (8.3°C) in November to a cold 37.2°F (2.9°C). An average low-temperature of 26.2°F (-3.2°C) is expected during December.Humidity
The average relative humidity in December in Saint Johns is 83%.Rainfall
In Saint Johns, in December, during 7.3 rainfall days, 0.87" (22mm) of precipitation is typically accumulated. In Saint Johns, during the entire year, the rain falls for 111.5 days and collects up to 11.34" (288mm) of precipitation.Snowfall
Months with snowfall in Saint Johns, Pennsylvania, are January through May, October through December. In Saint Johns, in December, snow falls for 5.3 days, with typically accumulated 1.02" (26mm) of snow. In Saint Johns, during the entire year, snow falls for 31.5 days and aggregates up to 7.28" (185mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:10 am and sunset at 4:36 pm. On the last day of December, in Saint Johns, Pennsylvania, sunrise is at 7:28 am and sunset at 4:45 pm EST.
Sunshine
The average sunshine in December is 3.9h.UV index
The months with the lowest UV index in Saint Johns, Pennsylvania, are January through March, October through December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for average individuals.Note: In December, a regular UV index of 2 translates into these guidelines:
Extended time in the sun generally does not harm most, but those with sensitive skin, infants, and children should always be protected. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Frequently asked questions
How cold is December in Saint Johns?
What is the average humidity in December in Saint Johns?
How many days does it rain in December in Saint Johns?
How many days does it snow in December in Saint Johns?
What is the month with the shortest days in Saint Johns?
How many hours of daylight does Saint Johns have in December?
When is the sunrise / sunset in December in Saint Johns?
How long on average sun shines in December in Saint Johns?
What is the month with the lowest UV index in Saint Johns?
What is the UV index intensity in December in Saint Johns?
Average temperature in December
Saint Johns, PA
- Average high temperature in December: 37.2°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (31.5°F).
- Average low temperature in December: 26.2°F
The month with the highest average low temperature is July (59.5°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Saint Johns, PA
- Average pressure in December: 30.09"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 Johns, PA
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is March (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in December
Saint Johns, PA
- Average humidity in December: 83%
The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is April (78%).
Average rainfall in December
Saint Johns, PA
- Average rainfall in December: 0.87"
The wettest month (with the highest rainfall) is May (1.26").
The driest month (with the least rainfall) is September (0.55").
Average rainfall days in December
Saint Johns, PA
- Average rainfall days in December: 7.3 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is January (5.4 days).
Average snowfall in December
Saint Johns, PA
- Average snowfall in December: 1.02"
The month with the highest snowfall is February (1.81").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Saint Johns, PA
- Average snowfall days in December: 5.3 days
The month with the highest number of snowfall days is January (9.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Saint Johns, 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: 3h and 5min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 36min).
Average sunshine days in December
Saint Johns, PA
- Average sunshine days in December: 19 days
The month with the most sunshine days is November (20.6 days).
The month with the least sunshine days is May (14.3 days).
Average UV index in December
Saint Johns, 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, October, November and December (UV index 2).
Average cloud cover in December
Saint Johns, PA
- Average cloud cover in December: 60
The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is July (Cloud cover 37).
Average visibility in December
Saint Johns, 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 Johns, Pennsylvania, USA
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