July weather forecast
Reston, VA

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Weather in July

July is a hot summer month in Reston, Virginia, with an average temperature ranging between min 68.5°F (20.3°C) and max 87.6°F (30.9°C).

Temperature

July, recognised by an average high temperature of 87.6°F (30.9°C) and a low of 68.5°F (20.3°C), is Reston's warmest month.

Heat index

The heat index value for July is calculated to be a very hot 98.6°F (37°C). Incorporate special precautions, risk of heat exhaustion and heat cramps is substantial. Sustained activity could cause heatstroke.
It is emphasized that the heat index's values are meant for shaded zones with mild winds. The heat index could experience an increase of 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is the result of factoring in humidity to the air temperature, indicating perceived warmth. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. Taking into account that direct sunlight can boost the heat effect, the heat index may rise by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. A higher relative humidity affects normal body cooling by reducing the evaporation rate, subsequently lowering the rate at which the body cools and increasing the perception of heat. Heat absorption that surpasses the body's shedding capability can lead to overheating and varying levels of dehydration.

Humidity

With an average relative humidity of 69%, July is the least humid month.

Rainfall

In Reston, in July, during 15.1 rainfall days, 2.68" (68mm) of precipitation is typically accumulated. In Reston, during the entire year, the rain falls for 152.8 days and collects up to 27.64" (702mm) of precipitation.

Snowfall

May through October are months without snowfall in Reston.

Daylight

In Reston, the average length of the day in July is 14h and 35min.
On the first day of July, sunrise is at 5:47 am and sunset at 8:38 pm. On the last day of the month, sunrise is at 6:10 am and sunset at 8:21 pm EDT.

Sunshine

July has the most sunshine of the year in Reston, Virginia, with an average of 10.7h 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 risk from unsafe exposure to UV radiation for the average person.
Note: An average UV index of 6 in July transforms into this advice:
Uphold preventive measures and conform to sun safety guidelines. Defending against skin and eye harm is crucial. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
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Frequently asked questions

What part of the year is the hottest in Reston?

The warmest period in Reston is July, when temperatures fluctuate between an average high of 87.6°F (30.9°C) and a low of 68.5°F (20.3°C).

How hot does it get in Reston in July?

The high-temperature, in July, in Reston, records 87.6°F (30.9°C), while the low-temperature is 68.5°F (20.3°C). In July, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is calculated to be 98.6°F (37°C).

What is the least humid month in Reston?

With an average relative humidity of 69%, July is the least humid month in Reston, Virginia.

What is the average humidity in July in Reston?

The average relative humidity in July in Reston, Virginia, is 69%.

How much does it rain in Reston in July?

In Reston, during July, the rain falls for 15.1 days and regularly aggregates up to 2.68" (68mm) of precipitation.

When it does not snow in Reston?

May through October are months without snowfall in Reston.

How many hours of daylight does Reston have in July?

The average day length in July in Reston, Virginia, is 14h and 35min.

When is the sunrise / sunset in July in Reston?

On the first day of July in Reston, Virginia, sunrise is at 5:47 am and sunset at 8:38 pm. On the last day of the month, sunrise is at 6:10 am and sunset at 8:21 pm EDT.

What month has the most sunshine in Reston?

July has the most sunshine of the year, with an average of 10.7h of sunshine.

How many hours of sunshine does Reston have in July?

The average sunshine duration in July in Reston, Virginia, is 10.7h.

What is the month with the highest UV index in Reston?

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

How high is the UV index in July in Reston?

In July, the average daily maximum UV index is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in July
Reston, VA

Average temperature in July - Reston, VA
  • Average high temperature in July: 87.6°F

The warmest month (with the highest average high temperature) is July (87.6°F).
The month with the lowest average high temperature is January (39.7°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 (26.4°F).

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Average pressure in July
Reston, VA

Average pressure in July - Reston, VA
  • Average pressure in July: 29.97"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

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Average wind speed in July
Reston, VA

Average wind speed in July - Reston, VA
  • Average wind speed in July: 5mph

The windiest month (with the highest average wind speed) is March (7.7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

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Average humidity in July
Reston, VA

Average humidity in July - Reston, VA
  • Average humidity in July: 69%

The months with the highest relative humidity are October and December (76%).
The month with the lowest relative humidity is July (69%).

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Average rainfall in July
Reston, VA

Average rainfall in July - Reston, VA
  • Average rainfall in July: 2.68"

The wettest month (with the highest rainfall) is August (3.39").
The driest month (with the least rainfall) is January (1.77").

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Average rainfall days in July
Reston, VA

Average rainfall days in July - Reston, VA
  • Average rainfall days in July: 15.1 days

The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is November (9.3 days).

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Average snowfall in July
Reston, VA

Average snowfall in July - Reston, VA
  • Average snowfall in July: 0"

The month with the highest snowfall is January (2.28").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in July
Reston, VA

Average snowfall days in July - Reston, VA
  • Average snowfall days in July: 0 days

The month with the highest number of snowfall days is January (4.6 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in July /
Average sunshine in July
Reston, VA

Average daylight in July / Average sunshine in July - Reston, VA
  • 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 30min).

  • Average sunshine in July: 10h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 0min).

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Average sunshine days in July
Reston, VA

Average sunshine days in July - Reston, VA
  • Average sunshine days in July: 13.9 days

The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is May (12.8 days).

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Average UV index in July
Reston, VA

Average UV index in July - Reston, VA
  • 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
Reston, VA

Average cloud cover in July - Reston, VA
  • Average cloud cover in July: 31

The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).

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Average visibility in July
Reston, VA

Average visibility in July - Reston, VA
  • Average visibility in July: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).

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Reston, Virginia, USA

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