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
Observing a mild shift, the average high-temperature during December reduces from November's frosty 46.9°F (8.3°C) to a cold 37.2°F (2.9°C). Throughout the month of December, Saint Johns observes an average nighttime temperature of 26.2°F (-3.2°C).Humidity
In December, the average relative humidity in Saint Johns is 83%.Rainfall
In Saint Johns, in December, it is raining for 7.3 days, with typically 0.87" (22mm) of accumulated precipitation. Throughout the year, there are 111.5 rainfall days, and 11.34" (288mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. In Saint Johns, during December, snow falls for 5.3 days and regularly aggregates up to 1.02" (26mm) of snow. In Saint Johns, Pennsylvania, during the entire year, snow falls for 31.5 days and aggregates up to 7.28" (185mm) of snow.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 4:36 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 4:45 pm EST.
Sunshine
The average sunshine in December is 3.9h.UV index
January through March, October through December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index, 2 in December, converts into the following recommendations:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Stay sun-safe with clothing that is both closely woven and worn loosely. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
How much does it rain in December?
How many days 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 in Saint Johns?
How long on average sun shines in December in Saint Johns?
What are the months with the lowest UV index?
How high is the UV index in December?
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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