August weather forecast
Herndon, VA

August in Herndon carries forward the balmy summer weather, with warm conditions persisting throughout the month. The month continues with a high averaging 85.6°F (29.8°C), a trend often associated with mid-late summer in Herndon. August can be hot, but not typically oppressive or uncomfortable, making it a favorable time to engage in a variety of outdoor activities. Despite the heat, Herndon's landscapes retain their summer allure, with the greenery standing tall and vibrant. The presence of longer daylight hours in August keeps the city alive and bustling for a larger part of the day.

Temperature

The arrival of August in Herndon is marked by an average high-temperature of a warm 85.6°F (29.8°C), bearing a close resemblance to July. Herndon's nights in August experience an average temperature drop to a refreshing 66°F (18.9°C).

Heat index

August's heat index is computed to be a very hot 95°F (35°C). Take more preventive steps, risk of heat exhaustion and heat cramps is elevated. Long activity may culminate in heatstroke.
It is essential to grasp that the heat index's numbers are for shade and light wind settings. Direct sunshine exposure could raise heat index values by as much as 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. A surge in relative humidity can disrupt the body's normal cooling function by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. Excessive heat gain, when not shed effectively by the body, can result in increasing body temperatures and related hazards.

Humidity

In August, the average relative humidity in Herndon is 72%.

Rainfall

August is the month with the most rainfall in Herndon. Rain falls for 16.7 days and accumulates 3.78" (96mm) of precipitation.

Snowfall

May through October are months without snowfall in Herndon, Virginia.

Daylight

In August, the average length of the day in Herndon is 13h and 38min.
On the first day of August in Herndon, 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 in Herndon is 10h.

UV index

May through August, with an average maximum UV index of 6, are months with the highest UV index in Herndon. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for average individuals.
Note: The UV index of 6 during August leads to these advisories:
Inhibit overexposure. Warding off sun damage is of utmost importance. Limit your direct sun exposure, especially between 10 a.m. and 4 p.m., when UV radiation is strongest. Shade structures might not provide complete sun protection. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.