July weather forecast
New Castle, DE

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Weather in July

July is the peak of summer in New Castle, setting record highs in terms of several weather parameters. It registers the highest average high temperature of the year at 84.9°F (29.4°C). Sunshine hours are also at their maximum, providing more opportunities for outdoor activities. Relative humidity, however, displays a downtrend. Despite being the warmest month, the city experiences a few rainy days, providing a brief respite from the summer heat.

Temperature

July is the month when New Castle's temperatures reach their peak, with averages of 84.9°F (29.4°C) and lows of 68.5°F (20.3°C).

Heat index

For July, the heat index is estimated at a torrid 95°F (35°C). More preventive actions are needed, risk of heat exhaustion and heat cramps is significant. Prolonged activity may trigger heatstroke.
Heat index guidelines indicate values are for light wind scenarios and shaded regions. The direct sunshine could escalate the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', melds the effects of warmth and moisture to generate a feeling of heat. Factors such as metabolic variations, being pregnant, and physical activity can impact an individual's weather perception. Direct sun rays can make one feel hotter, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Children regularly disregard the necessity to rest and replenish fluids. Thirst is a late symptom of dehydration - thus, maintaining hydration, particularly during long-lasting physical activities, is essential.
To achieve cooling, the human body employs perspiration, relying on the subsequent evaporation of sweat. Under high air temperature coupled with high humidity (high heat index), the body's perspiration is reduced, intensifying the sensation of heat. Increasing body temperatures can be a precursor to dehydration if the body can't shed the extra heat.

Humidity

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

Rainfall

In July, in New Castle, Delaware, the rain falls for 16.2 days. Throughout July, 2.4" (61mm) of precipitation is accumulated. Throughout the year, there are 143.2 rainfall days, and 21.89" (556mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall.

Ocean temperature

In New Castle, in July, the average water temperature is 74.3°F (23.5°C).
Note: Every individual's cold threshold differs, but factors like today's sunshine, wind, and temperature can tip the scales for a delightful swim in 74.3°F (23.5°C) waters. For reference, Olympians swim in waters of 77°F (25°C) to 82.4°F (28°C).

Daylight

The average length of the day in July in New Castle is 14h and 39min.
On the first day of the month, sunrise is at 5:38 am and sunset at 8:33 pm. On the last day of July, in New Castle, sunrise is at 6:01 am and sunset at 8:16 pm EDT.

Sunshine

The month with the most sunshine in New Castle, Delaware, is July, with an average of 10.8h of sunshine.

UV index

The months with the highest UV index are May through August, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the average person.
Note: The daily high UV index of 6 during July translates into the following recommendations:
Guard oneself from overexposure. Defence against sun injury is vital. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Be careful! The Sun's UV radiation is accentuated by reflecting off sand and water.
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Frequently asked questions

What are the warmest months in New Castle?

July, with average temperatures reaching a high of 84.9°F (29.4°C) and a low of 68.5°F (20.3°C), is the warmest month.

How hot does it get in New Castle in July?

The high-temperature, in July, in New Castle, records 84.9°F (29.4°C), while the low-temperature is 68.5°F (20.3°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), which combines relative humidity and air temperature, in July is estimated at 95°F (35°C).

What is the average humidity in July in New Castle?

The average relative humidity in July is 75%.

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

In July, in New Castle, the rain falls for 16.2 days. Throughout July, 2.4" (61mm) of precipitation is accumulated.

When it does not snow in New Castle?

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

What is the water temperature in July in New Castle?

In New Castle, the average seawater temperature in July is 74.3°F (23.5°C). For individuals prone to feeling cold, swimming in 73.4°F (23°C) is still regarded as intolerable. A wetsuit is not a necessity, but sunshine, wind, and air temperature are essential factors for relishing swimming at 74.3°F (23.5°C).

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

In New Castle, the average day length in July is 14h and 39min.

What time are sunrise and sunset in July in New Castle?

In July, on the first day of the month, sunrise is at 5:38 am and sunset at 8:33 pm. On the last day of the month, in New Castle, Delaware, sunrise is at 6:01 am and sunset at 8:16 pm EDT.

What month has the most sunshine in New Castle?

The month with the most sunshine in New Castle is July, with an average of 10.8h of sunshine.

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

In July, the average sunshine duration in New Castle is 10.8h.

What are the months with the highest UV index in New Castle?

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

What is the UV index intensity in July in New Castle?

In New Castle, the average daily maximum UV index in July is 6. A UV Index reading of 6 to 7 represents a high hazard to health from unprotected exposure to UV radiation.
Today
Tomorrow
Long-term
YearJFMAMJJulyASOND
Jun
July
Aug
Average high temperature
80.1°F 26.7°C
84.9°F 29.4°C
82.9°F 28.3°C
Average low temperature
63.1°F 17.3°C
68.5°F 20.3°C
66.9°F 19.4°C
Average pressure
29.94" 760mmHg
29.96" 761mmHg
29.99" 762mmHg
Average wind speed
6.5mph 10.5km/h
5.5mph 8.9km/h
5.4mph 8.7km/h
Average max. wind speed
7mph 11.3km/h
6mph 9.7km/h
6mph 9.7km/h
Average wind speed gusts
9.9mph 15.9km/h
8.5mph 13.7km/h
8.4mph 13.5km/h
Average humidity
76%
75%
75%
Average rainfall
2.01" 51mm
2.4" 61mm
2.83" 72mm
Average rainfall days
14.3
16.2
14.7
Average snowfall
0" 0mm
0" 0mm
0" 0mm
Average snowfall days
0
0
0
Average sea temperature
66.6°F 19.2°C
74.4°F 23.6°C
76.3°F 24.6°C
Average daylight
14h 5min
14h 4min
13h 4min
Average sunshine
10h 1min
10h 5min
10h 2min
Average sunshine days
13
12.3
14.2
Average UV index
6
6
6
Average cloud cover
35%
30%
32%
Average visibility
6mi 9.7km
6mi 9.7km
6mi 9.7km

Average temperature in July
New Castle, DE

Average temperature in July - New Castle, DE
  • Average high temperature in July: 84.9°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 July: 68.5°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 July
New Castle, DE

Average pressure in July - New Castle, DE
  • Average pressure in July: 29.96"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 July
New Castle, DE

Average wind speed in July - New Castle, DE
  • Average wind speed in July: 5.5mph

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 July
New Castle, DE

Average humidity in July - New Castle, DE
  • Average humidity in July: 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 July
New Castle, DE

Average rainfall in July - New Castle, DE
  • Average rainfall in July: 2.4"

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 July
New Castle, DE

Average rainfall days in July - New Castle, DE
  • Average rainfall days in July: 16.2 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 July
New Castle, DE

Average snowfall in July - New Castle, DE
  • Average snowfall in July: 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 July
New Castle, DE

Average snowfall days in July - New Castle, DE
  • Average snowfall days in July: 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 July
New Castle, DE

Average sea temperature in July - New Castle, DE
  • Average sea temperature in July: 74.4°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 July /
Average sunshine in July
New Castle, DE

Average daylight in July / Average sunshine in July - New Castle, DE
  • Average daylight in July: 14h 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 July: 10h and 5min

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 July
New Castle, DE

Average sunshine days in July - New Castle, DE
  • Average sunshine days in July: 12.3 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 July
New Castle, DE

Average UV index in July - New Castle, DE
  • Average UV index in July: 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 July
New Castle, DE

Average cloud cover in July - New Castle, DE
  • Average cloud cover in July: 30

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 July
New Castle, DE

Average visibility in July - New Castle, DE
  • Average visibility in July: 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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