August weather forecast
Mercersburg, PA

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Weather in August

August, the last month of the summer in Mercersburg, is also a moderately hot month, with temperature in the range of an average low of 61.3°F (16.3°C) and an average high of 82°F (27.8°C).

Temperature

With August's arrival, Mercersburg notes an average high-temperature of a still moderately hot 82°F (27.8°C), closely following the trend of the preceding month. During August, the nighttime temperature averages to a comfortable 61.3°F (16.3°C).

Heat index

Throughout August, the heat index is estimated at a hot 87.8°F (31°C). Persisting in activity during long-term exposure might induce weariness, with subsequent heat cramps.
Research indicates the heat index considers values in shaded locales and with light winds. A rise of up to 15 Fahrenheit (8 Celsius) degrees in the heat index could result from direct sunlight.
Note: The heat index, also known as 'feels like' or 'real feel', combines air temperature and relative humidity to represent a human perceived temperature equivalent. Additional factors encompassing metabolic differences, the level of physical activity, and clothing can impact the individual's perception of temperature. Do note, being directly under sun rays can amplify the heat you feel, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are of high significance for children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.

Humidity

In Mercersburg, the average relative humidity in August is 76%.

Rainfall

In Mercersburg, during August, the rain falls for 16.8 days and regularly aggregates up to 2.83" (72mm) of precipitation. In Mercersburg, during the entire year, the rain falls for 170.5 days and collects up to 31.02" (788mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In August, the average length of the day is 13h and 41min.
On the first day of August, sunrise is at 6:11 am and sunset at 8:24 pm. On the last day of the month, sunrise is at 6:39 am and sunset at 7:44 pm EDT.

Sunshine

In Mercersburg, the average sunshine in August is 10.2h.

UV index

The average daily maximum UV index in August is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the average person.
Note: A daily high UV index of 5 in August leads to these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Updated: Jul 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in August?

Mercersburg in August has an average high-temperature of 82°F (27.8°C) and an average low-temperature of 61.3°F (16.3°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is estimated at 87.8°F (31°C).

What is the average humidity in August?

In Mercersburg, the average relative humidity in August is 76%.

How many days does it rain in August?

In Mercersburg, Pennsylvania, in August, during 16.8 rainfall days, 2.83" (72mm) of precipitation is typically accumulated.

When it does not snow in Mercersburg?

In Mercersburg, snow does not fall in May through September.

What is the average length of the day in August?

In August, the average day length is 13h and 41min.

When is the sunrise / sunset in August?

On the first day of August, sunrise is at 6:11 am and sunset at 8:24 pm. On the last day of the month, sunrise is at 6:39 am and sunset at 7:44 pm EDT.

How long on average sun shines in August?

The average sunshine duration in August in Mercersburg is 10.2h.

How high is the UV index in August?

In August, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health threat from unprotected exposure to 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 August
Mercersburg, PA

Average temperature in August - Mercersburg, PA
  • Average high temperature in August: 82°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (35.2°F).

  • Average low temperature in August: 61.3°F

The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (22.1°F).

Average pressure in August
Mercersburg, PA

Average pressure in August - Mercersburg, PA
  • Average pressure in August: 30"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
Mercersburg, PA

Average wind speed in August - Mercersburg, PA
  • Average wind speed in August: 4.3mph

The windiest month (with the highest average wind speed) is January (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).

Average humidity in August
Mercersburg, PA

Average humidity in August - Mercersburg, PA
  • Average humidity in August: 76%

The months with the highest relative humidity are February, May, October and December (79%).
The months with the lowest relative humidity are April and July (75%).

Average rainfall in August
Mercersburg, PA

Average rainfall in August - Mercersburg, PA
  • Average rainfall in August: 2.83"

The wettest month (with the highest rainfall) is May (3.19").
The driest month (with the least rainfall) is September (2.05").

Average rainfall days in August
Mercersburg, PA

Average rainfall days in August - Mercersburg, PA
  • Average rainfall days in August: 16.8 days

The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is November (9.9 days).

Average snowfall in August
Mercersburg, PA

Average snowfall in August - Mercersburg, PA
  • Average snowfall in August: 0"

The month with the highest snowfall is January (5.2").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in August
Mercersburg, PA

Average snowfall days in August - Mercersburg, PA
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (9.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in August /
Average sunshine in August
Mercersburg, PA

Average daylight in August / Average sunshine in August - Mercersburg, PA
  • 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 24min).

  • Average sunshine in August: 10h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in August
Mercersburg, PA

Average sunshine days in August - Mercersburg, PA
  • Average sunshine days in August: 11.9 days

The month with the most sunshine days is November (18 days).
The month with the least sunshine days is May (10.3 days).

Average UV index in August
Mercersburg, PA

Average UV index in August - Mercersburg, PA
  • Average UV index in August: 5

The months with the highest UV index are May, June and July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in August
Mercersburg, PA

Average cloud cover in August - Mercersburg, PA
  • Average cloud cover in August: 33

The months with the most cloud cover are January, February and December (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in August
Mercersburg, PA

Average visibility in August - Mercersburg, PA
  • Average visibility in August: 5mi

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

Mercersburg, Pennsylvania, USA

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