December weather forecast and climate
New Castle, DE

Weather in December

The first month of the winter, December, is still a chilly month in New Castle, Delaware, with average temperature varying between 32.9°F (0.5°C) and 44.1°F (6.7°C).

Temperature

In December, the average high-temperature drops, from a cool 53.2°F (11.8°C) in November, to a frosty 44.1°F (6.7°C). In New Castle, in December, the average low-temperature is 32.9°F (0.5°C).

Humidity

The average relative humidity in New Castle, Delaware, is 77%.

Rainfall

In December, in New Castle, Delaware, the rain falls for 8.8 days. Throughout December, 1.85" (47mm) of precipitation is accumulated. Throughout the year, there are 143.2 rainfall days, and 21.89" (556mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In December, in New Castle, it is snowing for 2.4 days. Throughout December, 0.51" (13mm) of snow is accumulated. Throughout the year, there are 15 snowfall days, and 5.47" (139mm) of snow is accumulated.

Ocean temperature

In New Castle, the average seawater temperature is 48.6°F (9.2°C).
Note: 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.

Daylight

With an average of 9.4h of daylight, December has the shortest days of the year in New Castle.

Sunshine

The average sunshine in New Castle is 5.1h.

UV index

Months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from the exposure to the Sun's UV radiation for the ordinary person.
Note: The daily maximum UV index of 2 in December interpret into the following advice:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in New Castle?

In New Castle, Delaware, in December, the average high-temperature is 44.1°F (6.7°C), and the average low-temperature is 32.9°F (0.5°C).

What is the average humidity in December in New Castle?

The average relative humidity in December in New Castle, Delaware, is 77%.

How many days does it rain in December in New Castle?

In December, in New Castle, the rain falls for 8.8 days. Throughout December, 1.85" (47mm) of precipitation is accumulated.

How much does it snow in New Castle in December?

In December, it is snowing for 2.4 days. Throughout December, 0.51" (13mm) of snow is accumulated.

How cold is the water in December in New Castle?

In New Castle, Delaware, the average seawater temperature in December is 48.6°F (9.2°C). Swimming in 48.6°F (9.2°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

What is the month with the shortest days in New Castle?

With an average of 9.4h of daylight, December has the shortest days of the year in New Castle.

What is the average length of the day in December in New Castle?

In December, the average length of the day is 9.4h.

How many hours of sunshine does New Castle have in December?

In December, the average sunshine is 5.1h.

When is the lowest UV index in New Castle?

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

What is the UV index reading in December in New Castle?

The average daily maximum UV index in December in New Castle is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from the exposure to the Sun's UV radiation.

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).

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Average pressure in December
New Castle, DE

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

The month with the highest atmospheric pressure is November (30.13").
The month with the lowest atmospheric pressure is June (29.94").

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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).

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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%).

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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").

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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).

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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").
Months with the least snowfall are May, June, July, August, September and October (0").

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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).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

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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).

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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: 9.4h

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.4h).

  • Average sunshine in December: 5.1h

The month with the most sunshine is July (Average sunshine: 10.8h).
The month with the least sunshine is February (Average sunshine: 4.9h).

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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).

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Average UV index in December
New Castle, DE

Average UV index in December - New Castle, DE
  • Average UV index in December: 2

Months with the highest UV index are May, June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in December
New Castle, DE

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

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).

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Average visibility in December
New Castle, DE

Average visibility in December - New Castle, DE
  • Average visibility in December: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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