August weather forecast
Williamsville, IL

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Weather in August

The last month of the summer, August, is another warm month in Williamsville, Illinois, with temperature in the range of an average low of 64°F (17.8°C) and an average high of 81.7°F (27.6°C).

Temperature

The arrival of August brings an average high-temperature of a still warm 81.7°F (27.6°C), nearly identical to July's 82.8°F (28.2°C). Nighttime temperature lowers to an average of 64°F (17.8°C) in August.

Heat index

For most parts of August, the heat index is calculated to be a tropical 87.8°F (31°C). A sense of exhaustion might occur with extended exposure and activity, potentially causing heat cramps.
The standards for the heat index are set for locations in shade and under light breezes. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is derived by integrating air temperature with the existing relative humidity to express the perceived warmth. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for children. Young individuals are generally in more danger than adults due to their lower capacity to sweat. Moreover, their large skin surface in relation to their small bodies and the increased heat generation from their activities makes them more vulnerable.

Humidity

The average relative humidity in August is 82%.

Rainfall

In August, the rain falls for 12.8 days. Throughout August, 1.89" (48mm) of precipitation is accumulated. Throughout the year, in Williamsville, there are 131.5 rainfall days, and 18.54" (471mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall.

Daylight

In August, the average length of the day is 13h and 42min.
On the first day of the month, sunrise is at 5:57 am and sunset at 8:11 pm. On the last day of August, sunrise is at 6:25 am and sunset at 7:30 pm CDT.

Sunshine

In August, the average sunshine is 9.9h.

UV index

The months with the highest UV index are June 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 unsafe exposure to UV radiation for average individuals.
Note: A daily maximum UV index of 6 in August translates into the following instructions:
Persist in precautions and follow sun safety policies. Keeping sunburn at bay is imperative. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is particularly strong, noting that parasols or canopies may not offer total sun protection. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Updated: Jun 18, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Williamsville in August?

In August, the average high-temperature and low-temperature are 81.7°F (27.6°C) and 64°F (17.8°C) respectively. In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 87.8°F (31°C).

What is the average humidity in August?

In August, the average relative humidity is 82%.

How many days does it rain in August?

In Williamsville, in August, it is raining for 12.8 days, with typically 1.89" (48mm) of accumulated precipitation.

When it does not snow?

May through October are months without snowfall.

How many hours of daylight does Williamsville have in August?

In Williamsville, the average day length in August is 13h and 42min.

When is the sunrise / sunset in August?

In August, on the first day of the month, sunrise is at 5:57 am and sunset at 8:11 pm. On the last day of the month, sunrise is at 6:25 am and sunset at 7:30 pm CDT.

How long on average sun shines in August in Williamsville?

In August, the average sunshine duration is 9.9h.

What are the months with the highest UV index?

June 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 Williamsville, the average daily maximum UV index in August is 6. A UV Index reading of 6 to 7 represents a high health risk 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
Williamsville, IL

Average temperature in August - Williamsville, IL
  • Average high temperature in August: 81.7°F

The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.1°F).

  • Average low temperature in August: 64°F

The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).

Average pressure in August
Williamsville, IL

Average pressure in August - Williamsville, IL
  • Average pressure in August: 29.98"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in August
Williamsville, IL

Average wind speed in August - Williamsville, IL
  • Average wind speed in August: 6.2mph

The windiest months (with the highest average wind speed) are January and April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.2mph).

Average humidity in August
Williamsville, IL

Average humidity in August - Williamsville, IL
  • Average humidity in August: 82%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).

Average rainfall in August
Williamsville, IL

Average rainfall in August - Williamsville, IL
  • Average rainfall in August: 1.89"

The wettest month (with the highest rainfall) is June (2.36").
The driest month (with the least rainfall) is December (0.83").

Average rainfall days in August
Williamsville, IL

Average rainfall days in August - Williamsville, IL
  • Average rainfall days in August: 12.8 days

The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.7 days).

Average snowfall in August
Williamsville, IL

Average snowfall in August - Williamsville, IL
  • Average snowfall in August: 0"

The month with the highest snowfall is January (1.81").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in August
Williamsville, IL

Average snowfall days in August - Williamsville, IL
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (8 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
Williamsville, IL

Average daylight in August / Average sunshine in August - Williamsville, IL
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in August: 9h and 5min

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days in August
Williamsville, IL

Average sunshine days in August - Williamsville, IL
  • Average sunshine days in August: 14.7 days

The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is May (11.5 days).

Average UV index in August
Williamsville, IL

Average UV index in August - Williamsville, IL
  • Average UV index in August: 6

The months with the highest UV index are 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
Williamsville, IL

Average cloud cover in August - Williamsville, IL
  • Average cloud cover in August: 30

The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are June, August and September (Cloud cover 30).

Average visibility in August
Williamsville, IL

Average visibility in August - Williamsville, IL
  • Average visibility in August: 5mi

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

Williamsville, Illinois, USA

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