July weather forecast
Reston, VA

Weather in July

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

Temperature

July is the warmest month, with an average high-temperature of 87.6°F (30.9°C) and an average low-temperature of 68.5°F (20.3°C).

Heat index

The average heat index in July is computed to be a very hot 98.6°F (37°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature', 'apparent temperature', 'real feel', or 'feels like', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. Additional factors like differences in body mass, height, and shape, wind, metabolic differences, and activity influence one's weather impression. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 99.5°F (37.5°C) to 100.9°F (38.3°C), thermal conditions are potentially life-threatening.

Humidity

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

Rainfall

In Reston, during July, the rain falls for 15.1 days and regularly aggregates up to 2.68" (68mm) of precipitation. Throughout the year, in Reston, there are 152.8 rainfall days, and 27.64" (702mm) of precipitation is accumulated.

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 in Reston, sunrise is at 5:47 am and sunset at 8:39 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 8:22 pm EDT.

Sunshine

The month with the most sunshine in Reston is July, with an average of 10.7h of sunshine.

UV index

May through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In July, the average maximum UV index of 6 translate into the following recommendations:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the warmest month in Reston?

The warmest month in Reston, Virginia, is July, with an average high-temperature of 87.6°F (30.9°C) and an average low-temperature of 68.5°F (20.3°C).

What is the temperature in July in Reston?

The average high-temperature, in July, is 87.6°F (30.9°C), while the average low-temperature is 68.5°F (20.3°C). in July, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines relative humidity and air temperature, is computed to be 98.6°F (37°C).

What is the least humid month in Reston?

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

What is the average humidity in July in Reston?

In July, the average relative humidity in Reston is 69%.

How much does it rain in Reston in July?

In Reston, in July, it is raining for 15.1 days, with typically 2.68" (68mm) of accumulated precipitation.

When it does not snow in Reston?

In Reston, snow does not fall in May through October.

What is the average length of the day in July in Reston?

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

When is the sunrise / sunset in July in Reston?

On the first day of July, sunrise is at 5:47 am and sunset at 8:39 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 8:22 pm EDT.

What month has the most sunshine in Reston?

The month with the most sunshine in Reston, Virginia, is July, with an average of 10.7h of sunshine.

How long on average sun shines in July in Reston?

In Reston, the average sunshine duration in July is 10.7h.

What are the months with the highest UV index in Reston?

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

What is the UV index intensity in July in Reston?

In July, the average daily maximum UV index in Reston is 6. A UV Index estimate of 6 to 7 represents a high health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
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 35min

The month with the longest days is June (Average daylight: 14h and 52min).
The month with the shortest days is December (Average daylight: 9h and 29min).

  • Average sunshine in July: 10h and 42min

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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