December weather forecast
New Castle, DE

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Weather in December

December in New Castle is marked by the full arrival of winter. With temperatures further dropping, weather conditions become extremely cold. Snowfall of 0.51" (13mm) is recorded, welcoming the year's most festive season. As the shortest daylight hours of the year occur, New Castle's days become chilly and nights, colder. The high relative humidity keeps the temperatures from falling well below freezing.

Temperature

December involves a decrease in temperature, down from a fresh 53.2°F (11.8°C) in November to a frosty 44.1°F (6.7°C). Throughout the month of December, New Castle observes an average nighttime temperature of 32.9°F (0.5°C).

Humidity

In New Castle, the average relative humidity in December is 77%.

Rainfall

In New Castle, in December, during 8.8 rainfall days, 1.85" (47mm) of precipitation is typically accumulated. In New Castle, during the entire year, the rain falls for 143.2 days and collects up to 21.89" (556mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall. In New Castle, in December, snow falls for 2.4 days, with typically accumulated 0.51" (13mm) of snow. In New Castle, Delaware, during the entire year, snow falls for 15 days and aggregates up to 5.47" (139mm) of snow.

Ocean temperature

In New Castle, in December, the average water temperature is 48.6°F (9.2°C).
Note: Without suitable protection, venturing into 48.6°F (9.2°C) waters cooler than 50°F (10°C) can lead to pronounced cold shock and rapid breaths.

Daylight

The month with the shortest days is December, with an average of 9h and 24min of daylight.
On the first day of the month, sunrise is at 7:04 am and sunset at 4:38 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:48 pm EST.

Sunshine

In December, the average sunshine is 5.1h.

UV index

January, February, 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 unsafe exposure to UV radiation for the average person.
Note: An average UV index of 2 in December transforms into this advice:
Sun exposure does not present considerable issues for many, yet infants, fair-skinned people, and children necessitate constant protection. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. During bright days, sunglasses that offer UVA and UVB defense are recommended. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.

Frequently asked questions

How cold is December?

The high-temperature during December is 44.1°F (6.7°C) and the low-temperature is 32.9°F (0.5°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines air temperature and relative humidity, in August is evaluated at 89.6°F (32°C).

What is the average humidity in December?

In December, the average relative humidity is 77%.

How much does it rain in December?

In New Castle, in December, it is raining for 8.8 days, with typically 1.85" (47mm) of accumulated precipitation.

How many days does it snow in December?

In New Castle, in December, during 2.4 snowfall days, 0.51" (13mm) of snow is typically accumulated.

How cold is the water in December?

In New Castle, in December, the average water temperature is 48.6°F (9.2°C). Swimming in 48.6°F (9.2°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 24min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 25min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:48 pm EST.

How long on average sun shines in December?

The average sunshine duration in December is 5.1h.

When is the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December?

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
New Castle, DE

Average temperature in December - New Castle, DE
  • Average high temperature in December: 44.1°F

The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (37.8°F).

  • Average low temperature in December: 32.9°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.1°F).

Average pressure in December
New Castle, DE

Average pressure in December - New Castle, DE
  • Average pressure in December: 30.1"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
New Castle, DE

Average wind speed in December - New Castle, DE
  • Average wind speed in December: 8.1mph

The windiest months (with the highest average wind speed) are February and March (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).

Average humidity in December
New Castle, DE

Average humidity in December - New Castle, DE
  • Average humidity in December: 77%

The month with the highest relative humidity is October (78%).
The month with the lowest relative humidity is April (72%).

Average rainfall in December
New Castle, DE

Average rainfall in December - New Castle, DE
  • Average rainfall in December: 1.85"

The wettest month (with the highest rainfall) is August (2.83").
The driest month (with the least rainfall) is January (1.38").

Average rainfall days in December
New Castle, DE

Average rainfall days in December - New Castle, DE
  • Average rainfall days in December: 8.8 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (7.8 days).

Average snowfall in December
New Castle, DE

Average snowfall in December - New Castle, DE
  • Average snowfall in December: 0.51"

The month with the highest snowfall is January (1.69").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
New Castle, DE

Average snowfall days in December - New Castle, DE
  • Average snowfall days in December: 2.4 days

The month with the highest number of snowfall days is January (5.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in December
New Castle, DE

Average sea temperature in December - New Castle, DE
  • Average sea temperature in December: 48.5°F

The best month for swimming (with the highest average sea temperature) is August (76.3°F).
The coldest month (with the lowest average sea temperature) is February (40.9°F).

Average daylight in December /
Average sunshine in December
New Castle, DE

Average daylight in December / Average sunshine in December - New Castle, DE
  • Average daylight in December: 9h and 2min

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 24min).

  • Average sunshine in December: 5h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).

Average sunshine days in December
New Castle, DE

Average sunshine days in December - New Castle, DE
  • Average sunshine days in December: 19.1 days

The month with the most sunshine days is November (20.1 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in December
New Castle, DE

Average UV index in December - New Castle, 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, February, November and December (UV index 2).

Average cloud cover in December
New Castle, DE

Average cloud cover in December - New Castle, DE
  • Average cloud cover in December: 45

The months with the most cloud cover are February and March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).

Average visibility in December
New Castle, DE

Average visibility in December - New Castle, 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).

New Castle, Delaware, USA

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