August weather forecast
Rockville, MD

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Weather in August

August retains the traits of Rockville's warm summer, though with temperatures slightly falling from the July highs to a range of 85.3°F (29.6°C) and 67.5°F (19.7°C). This month transitions the switch from summer to autumn, impacting the city's weather. It's a period of long sunny days interspersed with periods of rainfall adding dynamism to the city's climate. As the end of the month beckons, the days start to get shorter, hinting at the onset of the autumn season.

Temperature

August's average high-temperature stands at a warm 85.3°F (29.6°C), showing little deviation from July's 87.1°F (30.6°C). Rockville experiences a nighttime temperature average of 67.5°F (19.7°C) during August.

Heat index

The heat index for August is calculated to be a fiery hot 95°F (35°C). Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
Realize that the values for the heat index are set for shaded places and light winds. Direct sunlight exposure may result in a rise of the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', 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. You should know that direct sun exposure can heighten weather effects, potentially elevating the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Children frequently underestimate the necessity to rest and hydrate. Thirst is a late sign of dehydration - thus, it is vital to stay hydrated, particularly during lengthy physical exercises.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. When the air contains significant moisture, the efficiency of the evaporation process decreases, preventing the body from cooling down effectively and creating a feeling of overheating. As body temperatures escalate without effective heat release, one might face dehydration threats.

Humidity

The average relative humidity in August is 72%.

Rainfall

August is the month with the most rainfall. Rain falls for 15.9 days and accumulates 3.9" (99mm) of precipitation.

Snowfall

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

Daylight

In August, the average length of the day in Rockville, Maryland, is 13h and 39min.
On the first day of August, sunrise is at 6:09 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 6:37 am and sunset at 7:40 pm EDT.

Sunshine

In August, the average sunshine is 10.3h.

UV index

The months with the highest UV index are May through August, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: A maximum high UV index of 6 in August translates into the following recommendations:
Undertake protective measures and comply with sun safety rules. Shielding against skin and eye damage is essential. Between 10 a.m. and 4 p.m., UV radiation is strongest. Make an effort to avoid direct sunlight during this time, remembering that shade structures may not provide full sun protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.

Frequently asked questions

How hot is August?

During August, Rockville experiences an average high-temperature of 85.3°F (29.6°C) and a low-temperature of 67.5°F (19.7°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, in August is calculated to be 95°F (35°C).

What is the average humidity in August in Rockville?

In August, the average relative humidity is 72%.

What is the wettest month?

August is the month with the most rainfall in Rockville. Rain falls for 15.9 days and accumulates 3.9" (99mm) of precipitation.

How many days does it rain in August?

In Rockville, in August, during 15.9 rainfall days, 3.9" (99mm) of precipitation is typically accumulated.

When it does not snow?

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

What is the average length of the day in August?

In August, the average day length is 13h and 39min.

When are sunrise and sunset in August?

On the first day of August, sunrise is at 6:09 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 6:37 am and sunset at 7:40 pm EDT.

How many hours of sunshine does Rockville have in August?

The average sunshine duration in August is 10.3h.

What is the month with the highest UV index?

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

What is the UV index intensity in August?

In Rockville, the average daily maximum UV index in August is 6. A UV Index reading of 6 to 7 represents a high health threat from exposure to Sun's UV rays.
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 August
Rockville, MD

Average temperature in August - Rockville, MD
  • Average high temperature in August: 85.3°F

The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (39°F).

  • Average low temperature in August: 67.5°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 (26.2°F).

Average pressure in August
Rockville, MD

Average pressure in August - Rockville, MD
  • 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
Rockville, MD

Average wind speed in August - Rockville, MD
  • Average wind speed in August: 5mph

The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (5mph).

Average humidity in August
Rockville, MD

Average humidity in August - Rockville, MD
  • Average humidity in August: 72%

The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is July (70%).

Average rainfall in August
Rockville, MD

Average rainfall in August - Rockville, MD
  • Average rainfall in August: 3.9"

The wettest month (with the highest rainfall) is August (3.9").
The driest month (with the least rainfall) is January (1.97").

Average rainfall days in August
Rockville, MD

Average rainfall days in August - Rockville, MD
  • Average rainfall days in August: 15.9 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is November (9.2 days).

Average snowfall in August
Rockville, MD

Average snowfall in August - Rockville, MD
  • Average snowfall in August: 0"

The month with the highest snowfall is March (3.03").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in August
Rockville, MD

Average snowfall days in August - Rockville, MD
  • Average snowfall days in August: 0 days

The months with the highest number of snowfall days are January and February (5.3 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
Rockville, MD

Average daylight in August / Average sunshine in August - Rockville, MD
  • 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 2min

The month with the most sunshine is July (Average sunshine: 10h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 6min).

Average sunshine days in August
Rockville, MD

Average sunshine days in August - Rockville, MD
  • Average sunshine days in August: 12.8 days

The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is July (12 days).

Average UV index in August
Rockville, MD

Average UV index in August - Rockville, MD
  • 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
Rockville, MD

Average cloud cover in August - Rockville, MD
  • Average cloud cover in August: 32

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).

Average visibility in August
Rockville, MD

Average visibility in August - Rockville, MD
  • 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).

Rockville, Maryland, USA

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