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
Grand Valley's progression into December includes a drop in the average high-temperature, from a chilly 45.1°F (7.3°C) in November to an icy 35.6°F (2°C). Grand Valley records an average nighttime low of 25.7°F (-3.5°C) in December.Humidity
The average relative humidity in December is 88%.Rainfall
In Grand Valley, during December, the rain falls for 10.5 days and regularly aggregates up to 1.89" (48mm) of precipitation. In Grand Valley, during the entire year, the rain falls for 160.2 days and collects up to 23.43" (595mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Grand Valley, during December, snow falls for 18.1 days and regularly aggregates up to 5.63" (143mm) of snow. Throughout the year, there are 85.6 snowfall days, and 26.54" (674mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 7:26 am and sunset at 4:48 pm. On the last day of the month, sunrise is at 7:45 am and sunset at 4:57 pm EST.
Sunshine
In Grand Valley, the average sunshine in December is 2.5h.UV index
January, February and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for the average person.Note: In December, the maximum UV index of 1 suggests this advice:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.
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 Grand Valley in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Grand Valley have in December?
What time are sunrise and sunset in December?
How long on average sun shines in December in Grand Valley?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Grand Valley, PA
- Average high temperature in December: 35.6°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is January (29.5°F).
- Average low temperature in December: 25.7°F
The month with the highest average low temperature is July (58.6°F).
The coldest month (with the lowest average low temperature) is January (18°F).
Average pressure in December
Grand Valley, PA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Grand Valley, PA
- Average wind speed in December: 8.2mph
The windiest month (with the highest average wind speed) is January (8.8mph).
The calmest month (with the lowest average wind speed) is July (5.4mph).
Average humidity in December
Grand Valley, PA
- Average humidity in December: 88%
The month with the highest relative humidity is February (90%).
The month with the lowest relative humidity is May (79%).
Average rainfall in December
Grand Valley, PA
- Average rainfall in December: 1.89"
The wettest month (with the highest rainfall) is April (2.32").
The driest month (with the least rainfall) is November (1.57").
Average rainfall days in December
Grand Valley, PA
- Average rainfall days in December: 10.5 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is February (7.5 days).
Average snowfall in December
Grand Valley, PA
- Average snowfall in December: 5.63"
The month with the highest snowfall is January (7.28").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Grand Valley, PA
- Average snowfall days in December: 18.1 days
The month with the highest number of snowfall days is January (21.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Grand Valley, PA
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 2h and 3min
The months with the most sunshine are July and August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 2h and 12min).
Average sunshine days in December
Grand Valley, PA
- Average sunshine days in December: 6.9 days
The month with the most sunshine days is October (13.3 days).
The month with the least sunshine days is January (5.3 days).
Average UV index in December
Grand Valley, PA
- Average UV index in December: 1
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February and December (UV index 1).
Average cloud cover in December
Grand Valley, PA
- Average cloud cover in December: 75
The month with the most cloud cover is January (Cloud cover 78).
The months with the least cloud cover are July and August (Cloud cover 37).
Average visibility in December
Grand Valley, PA
- Average visibility in December: 4mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (5mi).
The months with the lowest visibility are January, February and December (4mi).
Grand Valley, Pennsylvania, USA
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