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
The commencement of December indicates a shift in the average high-temperature, receding from November's cool 50.2°F (10.1°C) to a cold 40.8°F (4.9°C). Throughout December, Harrow records an average temperature of 29.1°F (-1.6°C) at night.Humidity
In December, the average relative humidity in Harrow is 80%.Rainfall
In Harrow, Pennsylvania, during December, the rain falls for 5.8 days and regularly aggregates up to 0.79" (20mm) of precipitation. In Harrow, during the entire year, the rain falls for 91.3 days and collects up to 7.28" (185mm) of precipitation.Snowfall
January through May, November and December are months with snowfall in Harrow. In December, in Harrow, it is snowing for 2.2 days. Throughout December, 0.59" (15mm) of snow is accumulated. In Harrow, during the entire year, snow falls for 14.8 days and aggregates up to 2.24" (57mm) of snow.Daylight
The month with the shortest days in Harrow is December, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:05 am and sunset at 4:34 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:44 pm EST.
Sunshine
In December, the average sunshine is 4.7h.UV index
The months with the lowest UV index in Harrow are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV rays for the average person.Note: An average maximum UV index of 2 in December leads to these recommendations:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. To protect against the Sun's most potent rays, avoid direct exposure around midday. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold in Harrow during December?
What is the average humidity in December in Harrow?
How many days does it rain in December in Harrow?
How much does it snow in Harrow in December?
What is the month with the shortest days in Harrow?
What is the average length of the day in December in Harrow?
What time are sunrise and sunset in December in Harrow?
How long on average sun shines in December in Harrow?
What is the month with the lowest UV index in Harrow?
What is the UV index intensity in December in Harrow?
Average temperature in December
Harrow, PA
- Average high temperature in December: 40.8°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 (34.9°F).
- Average low temperature in December: 29.1°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in December
Harrow, 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
Harrow, PA
- Average wind speed in December: 7.6mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in December
Harrow, PA
- Average humidity in December: 80%
The month with the highest relative humidity is February (81%).
The months with the lowest relative humidity are April and July (76%).
Average rainfall in December
Harrow, PA
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is July (0.91").
The driest month (with the least rainfall) is September (0.28").
Average rainfall days in December
Harrow, PA
- Average rainfall days in December: 5.8 days
The months with the highest number of rainy days are June and July (10.2 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in December
Harrow, PA
- Average snowfall in December: 0.59"
The month with the highest snowfall is March (0.63").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Harrow, PA
- Average snowfall days in December: 2.2 days
The month with the highest number of snowfall days is February (4.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Harrow, 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 30min).
Average sunshine days in December
Harrow, PA
- Average sunshine days in December: 22.8 days
The month with the most sunshine days is January (23.8 days).
The month with the least sunshine days is June (16.7 days).
Average UV index in December
Harrow, 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
Harrow, PA
- Average cloud cover in December: 50
The months with the most cloud cover are February and December (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 34).
Average visibility in December
Harrow, PA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, November and December (6mi).
The months with the lowest visibility are May, June, July, August, September and October (5mi).
Harrow, Pennsylvania, USA
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