Contents
- Weather in August
- Frequently asked questions
- Average temperature in August
- Average pressure in August
- Average wind speed in August
- Average humidity in August
- Average rainfall in August
- Average rainfall days in August
- Average snowfall in August
- Average snowfall days in August
- Average daylight in August
- Average sunshine in August
- Average sunshine days in August
- Average UV index in August
- Average cloud cover in August
- Average visibility in August
Weather in August
Temperature
August's advent presents an average high-temperature of a moderately hot 85.6°F (29.8°C), indicating a slight variation from the conditions of the previous month. In Herndon, August nights cool down to an average of 66°F (18.9°C).Heat index
August's heat index is computed to be a sweltering 95°F (35°C). Take more caution, heat exhaustion and heat cramps may occur. Long-lasting activity may cause heatstroke.Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is an estimation of the warmth sensation when considering humidity levels. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. One should be aware that direct sunshine can amplify the perceived temperature, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for children. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
In response to overheating, the human body perspires to cool down, mainly through the evaporation of sweat. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. Overheating and dehydration threats arise when heat gain goes beyond what the body can comfortably shed.
Humidity
The average relative humidity in August is 72%.Rainfall
The month with the most rainfall is August, when the rain falls for 16.7 days and typically aggregates up to 3.78" (96mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In Herndon, Virginia, the average length of the day in August is 13h and 38min.On the first day of August, sunrise is at 6:11 am and sunset at 8:20 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 7:41 pm EDT.
Sunshine
In August, the average sunshine is 10h.UV index
May through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: The daily high UV index of 6 during August translates into the following recommendations:
Escape overexposure. People with light skin may incur burns in fewer than 20 minutes. Avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is most intense, and remember that not all shade structures provide full protection. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is August?
What is the average humidity in August?
What is the rainiest month?
How much does it rain in August?
When it does not snow in Herndon?
How many hours of daylight does Herndon have in August?
What time are sunrise and sunset in August?
How many hours of sunshine does Herndon have in August?
When is the highest UV index?
What is the UV index intensity in August?
Average temperature in August
Herndon, VA
- Average high temperature in August: 85.6°F
The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in August: 66°F
The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is January (25.9°F).
Average pressure in August
Herndon, VA
- Average pressure in August: 29.99"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).
Average wind speed in August
Herndon, VA
- Average wind speed in August: 4.7mph
The windiest month (with the highest average wind speed) is March (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in August
Herndon, VA
- Average humidity in August: 72%
The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is July (70%).
Average rainfall in August
Herndon, VA
- Average rainfall in August: 3.78"
The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (1.93").
Average rainfall days in August
Herndon, VA
- Average rainfall days in August: 16.7 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (9.3 days).
Average snowfall in August
Herndon, VA
- Average snowfall in August: 0"
The month with the highest snowfall is January (3.54").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in August
Herndon, VA
- Average snowfall days in August: 0 days
The months with the highest number of snowfall days are January and February (5.1 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in August /
Average sunshine in August
Herndon, VA
- 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 30min).
- Average sunshine in August: 10h and 0min
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).
Average sunshine days in August
Herndon, VA
- Average sunshine days in August: 12.1 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in August
Herndon, VA
- 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).
Average cloud cover in August
Herndon, VA
- Average cloud cover in August: 34
The month with the most cloud cover is March (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in August
Herndon, VA
- Average visibility in August: 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).
Herndon, Virginia, USA
Weather forecast for your location
2. Allow the app to use your location