August weather forecast
New Castle, DE

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Weather in August

In New Castle, August continues the warm weather pattern established in July. The city's weather is characterized by high temperatures, similar to those in July. Despite these high temperatures, August witnesses the highest rainfall of the year at 2.83" (72mm), providing relief from the sun. The sea temperature remains elevated, attracting beachgoers. Wind velocity maintains a slow pace, contributing to the calm summer atmosphere.

Temperature

New Castle marks the onset of August with an average high-temperature of a still warm 82.9°F (28.3°C), subtly divergent from July's 84.9°F (29.4°C). August brings New Castle a consistent average low-temperature of 66.9°F (19.4°C).

Heat index

In August, the average heat index is estimated at a hot 89.6°F (32°C). With extended exposure and activity, one might feel exhausted and experience heat cramps.
When referencing the heat index, its values are suitable for shady environments and light breezes. Exposure to the direct sun might augment heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', blends air temperature and moisture content to represent the felt temperature to humans. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. With the sun shining directly, it's crucial to understand that it can increase the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for babies and toddlers. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.

Humidity

In New Castle, the average relative humidity in August is 75%.

Rainfall

August is the month with the most rainfall in New Castle. Rain falls for 14.7 days and accumulates 2.83" (72mm) of precipitation.

Snowfall

In New Castle, snow does not fall in May through October.

Ocean temperature

The month with the warmest seawater in New Castle is August, with an average ocean temperature of 76.3°F (24.6°C).
Note: Factor in your tolerance to cold, the sunshine, the wind, and the air's warmth, and a swim in 76.3°F (24.6°C) might be tempting. It is interesting to note that Olympians compete in 77°F (25°C) to 82.4°F (28°C) water temperatures.

Daylight

In New Castle, the average length of the day in August is 13h and 41min.
On the first day of the month, sunrise is at 6:02 am and sunset at 8:14 pm. On the last day of August, sunrise is at 6:30 am and sunset at 7:34 pm EDT.

Sunshine

The average sunshine in August is 10.3h.

UV index

May through August, with an average maximum UV index of 6, are months with the highest UV index in New Castle. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum UV index of 6 during August translates into these guidelines:
Deflect overexposure. Sun protection is a necessity. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Caution! The reflection of sand and water significantly amplifies the Sun's UV radiation.
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Frequently asked questions

How hot does it get in New Castle in August?

The high-temperature in New Castle, Delaware, during August is 82.9°F (28.3°C) and the low-temperature is 66.9°F (19.4°C). In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 89.6°F (32°C).

What is the average humidity in August in New Castle?

In August, the average relative humidity in New Castle, Delaware, is 75%.

What is the wettest month in New Castle?

August is the month with the most rainfall in New Castle, Delaware. Rain falls for 14.7 days and accumulates 2.83" (72mm) of precipitation.

How much does it rain in New Castle in August?

In New Castle, in August, it is raining for 14.7 days, with typically 2.83" (72mm) of accumulated precipitation.

When it does not snow in New Castle?

In New Castle, Delaware, snow does not fall in May through October.

What month is the ocean warmest in New Castle?

August is the month with the warmest seawater in New Castle, Delaware, with an average ocean temperature of 76.3°F (24.6°C).

How warm is the water in August in New Castle?

In August, the average ocean temperature in New Castle is 76.3°F (24.6°C). A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 76.3°F (24.6°C) water.

How many hours of daylight does New Castle have in August?

In New Castle, Delaware, the average day length in August is 13h and 41min.

When is the sunrise / sunset in August in New Castle?

In August, on the first day of the month, sunrise is at 6:02 am and sunset at 8:14 pm. On the last day of the month, in New Castle, Delaware, sunrise is at 6:30 am and sunset at 7:34 pm EDT.

How long on average sun shines in August in New Castle?

In New Castle, the average sunshine duration in August is 10.3h.

When is the highest UV index in New Castle?

The months with the highest UV index in New Castle are May through August, with an average maximum UV index of 6.

How high is the UV index in August in New Castle?

In New Castle, the average daily maximum UV index in August is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to Sun's UV rays.
Today
Tomorrow
Long-term
YearJFMAMJJAugustSOND
Jul
August
Sep
Average high temperature
84.9°F 29.4°C
82.9°F 28.3°C
76.3°F 24.6°C
Average low temperature
68.5°F 20.3°C
66.9°F 19.4°C
60.6°F 15.9°C
Average pressure
29.96" 761mmHg
29.99" 762mmHg
30.05" 763mmHg
Average wind speed
5.5mph 8.9km/h
5.4mph 8.7km/h
6mph 9.7km/h
Average max. wind speed
6mph 9.7km/h
6mph 9.7km/h
6.2mph 10km/h
Average wind speed gusts
8.5mph 13.7km/h
8.4mph 13.5km/h
9.3mph 15km/h
Average humidity
75%
75%
77%
Average rainfall
2.4" 61mm
2.83" 72mm
1.42" 36mm
Average rainfall days
16.2
14.7
11.2
Average snowfall
0" 0mm
0" 0mm
0" 0mm
Average snowfall days
0
0
0
Average sea temperature
74.4°F 23.6°C
76.3°F 24.6°C
72.1°F 22.3°C
Average daylight
14h 4min
13h 4min
12h 2min
Average sunshine
10h 5min
10h 2min
9h 1min
Average sunshine days
12.3
14.2
17.6
Average UV index
6
6
5
Average cloud cover
30%
32%
35%
Average visibility
6mi 9.7km
6mi 9.7km
6mi 9.7km

Average temperature in August
New Castle, DE

Average temperature in August - New Castle, DE
  • Average high temperature in August: 82.9°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 August: 66.9°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 August
New Castle, DE

Average pressure in August - New Castle, DE
  • Average pressure in August: 29.99"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).

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Average wind speed in August
New Castle, DE

Average wind speed in August - New Castle, DE
  • Average wind speed in August: 5.4mph

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 August
New Castle, DE

Average humidity in August - New Castle, DE
  • Average humidity in August: 75%

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 August
New Castle, DE

Average rainfall in August - New Castle, DE
  • Average rainfall in August: 2.83"

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 August
New Castle, DE

Average rainfall days in August - New Castle, DE
  • Average rainfall days in August: 14.7 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 August
New Castle, DE

Average snowfall in August - New Castle, DE
  • Average snowfall in August: 0"

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").

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Average snowfall days in August
New Castle, DE

Average snowfall days in August - New Castle, DE
  • Average snowfall days in August: 0 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).

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Average sea temperature in August
New Castle, DE

Average sea temperature in August - New Castle, DE
  • Average sea temperature in August: 76.3°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 August /
Average sunshine in August
New Castle, DE

Average daylight in August / Average sunshine in August - New Castle, DE
  • Average daylight in August: 13h and 4min

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 August: 10h and 2min

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).

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Average sunshine days in August
New Castle, DE

Average sunshine days in August - New Castle, DE
  • Average sunshine days in August: 14.2 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 August
New Castle, DE

Average UV index in August - New Castle, DE
  • Average UV index in August: 6

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).

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Average cloud cover in August
New Castle, DE

Average cloud cover in August - New Castle, DE
  • Average cloud cover in August: 32

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).

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Average visibility in August
New Castle, DE

Average visibility in August - New Castle, DE
  • Average visibility in August: 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).

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New Castle, Delaware, USA

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