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 start of December signals a gentle decrease in the average high-temperature, transitioning from a cool 54°F (12.2°C) in November to a frosty 45.9°F (7.7°C). In December, Hartly reports a consistent average low-temperature of 34.7°F (1.5°C) during the nights.Humidity
The average relative humidity in December in Hartly is 77%.Rainfall
In Hartly, in December, during 11.5 rainfall days, 3.43" (87mm) of precipitation is typically accumulated. In Hartly, during the entire year, the rain falls for 169.2 days and collects up to 34.96" (888mm) of precipitation.Snowfall
January through April, November and December are months with snowfall in Hartly. In December, in Hartly, it is snowing for 2.5 days. Throughout December, 0.91" (23mm) of snow is accumulated. In Hartly, during the entire year, snow falls for 14.4 days and aggregates up to 7.44" (189mm) of snow.Daylight
With an average of 9h and 30min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:03 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:50 pm EST.
Sunshine
The average sunshine in December is 5.2h.UV index
January 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 average person.Note: In December, the maximum UV index of 2 translates into these guidelines:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Frequently asked questions
What is the usual temperature for Hartly in December?
What is the average humidity in December in Hartly?
How much does it rain in Hartly in December?
How much does it snow in Hartly in December?
What is the month with the shortest days in Hartly?
What is the average length of the day in December in Hartly?
When are sunrise and sunset in December in Hartly?
How many hours of sunshine does Hartly have in December?
What are the months with the lowest UV index in Hartly?
How high is the UV index in December in Hartly?
Average temperature in December
Hartly, DE
- Average high temperature in December: 45.9°F
The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (39.2°F).
- Average low temperature in December: 34.7°F
The month with the highest average low temperature is July (69.3°F).
The coldest month (with the lowest average low temperature) is January (27.9°F).
Average pressure in December
Hartly, DE
- Average pressure in December: 30.1"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
Hartly, DE
- Average wind speed in December: 8.7mph
The windiest months (with the highest average wind speed) are February and March (9.5mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in December
Hartly, DE
- Average humidity in December: 77%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is April (73%).
Average rainfall in December
Hartly, DE
- Average rainfall in December: 3.43"
The wettest month (with the highest rainfall) is August (3.86").
The driest month (with the least rainfall) is January (2.13").
Average rainfall days in December
Hartly, DE
- Average rainfall days in December: 11.5 days
The month with the highest number of rainy days is July (19 days).
The month with the least rainy days is November (9.3 days).
Average snowfall in December
Hartly, DE
- Average snowfall in December: 0.91"
The month with the highest snowfall is March (2.6").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Hartly, DE
- Average snowfall days in December: 2.5 days
The month with the highest number of snowfall days is January (4.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Hartly, DE
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 5h and 6min).
Average sunshine days in December
Hartly, DE
- Average sunshine days in December: 16.8 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (9.5 days).
Average UV index in December
Hartly, DE
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in December
Hartly, DE
- Average cloud cover in December: 44
The months with the most cloud cover are February and March (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 29).
Average visibility in December
Hartly, DE
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Hartly, Delaware, USA
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