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
Mertztown's average high-temperature decreases in December, falling from a fresh 50°F (10°C) in November to a wintry 40.3°F (4.6°C). In the month of December, the nighttime temperature in Mertztown dips to a steady average of 28.9°F (-1.7°C).Humidity
In Mertztown, the average relative humidity in December is 80%.Rainfall
In Mertztown, during December, the rain falls for 11.2 days and regularly aggregates up to 2.68" (68mm) of precipitation. In Mertztown, during the entire year, the rain falls for 155.8 days and collects up to 30.75" (781mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Mertztown, Pennsylvania, during December, snow falls for 5 days and regularly aggregates up to 2.36" (60mm) of snow. In Mertztown, Pennsylvania, during the entire year, snow falls for 29.4 days and aggregates up to 15.87" (403mm) of snow.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 7:07 am and sunset at 4:36 pm. On the last day of December, sunrise is at 7:25 am and sunset at 4:46 pm EST.
Sunshine
The average sunshine in December in Mertztown is 4.7h.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 estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: A daily maximum UV index of 2 in December translates into the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Experience reduced UV exposure by about half when donning a wide-brim hat. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is December cold?
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?
When is the sunrise / sunset in December?
How many hours of sunshine does Mertztown have in December?
What is the month with the lowest UV index in Mertztown?
What is the UV index reading in December?
Average temperature in December
Mertztown, PA
- Average high temperature in December: 40.3°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (34.3°F).
- Average low temperature in December: 28.9°F
The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).
Average pressure in December
Mertztown, PA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Mertztown, PA
- Average wind speed in December: 7.6mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).
Average humidity in December
Mertztown, PA
- Average humidity in December: 80%
The month with the highest relative humidity is February (82%).
The months with the lowest relative humidity are April and July (76%).
Average rainfall in December
Mertztown, PA
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is April (2.99").
The driest month (with the least rainfall) is September (1.77").
Average rainfall days in December
Mertztown, PA
- Average rainfall days in December: 11.2 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (8.5 days).
Average snowfall in December
Mertztown, PA
- Average snowfall in December: 2.36"
The month with the highest snowfall is March (4.29").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Mertztown, PA
- Average snowfall days in December: 5 days
The month with the highest number of snowfall days is January (8.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mertztown, 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 4min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 24min).
Average sunshine days in December
Mertztown, PA
- Average sunshine days in December: 16.6 days
The month with the most sunshine days is November (17.9 days).
The month with the least sunshine days is April (11.2 days).
Average UV index in December
Mertztown, 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
Mertztown, PA
- Average cloud cover in December: 51
The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 33).
Average visibility in December
Mertztown, PA
- Average visibility in December: 5mi
The months with the highest visibility are April, June, July and November (6mi).
The months with the lowest visibility are January, February, March, May, August, September, October and December (5mi).
Mertztown, Pennsylvania, USA
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