August weather forecastWilliamson, IL
August
Weather in August
August, the last month of the summer in Williamson, is another warm month, with an average temperature ranging between min 65.5°F (18.6°C) and max 82.9°F (28.3°C).Temperature
The advent of August reveals an average high-temperature of a still warm 82.9°F (28.3°C), showing minimal difference from the prior month. Williamson's nighttime temperature in August drops to an average of 65.5°F (18.6°C).Heat index
During August, the heat index is computed to be a tropical 91.4°F (33°C). Greater safety measures are needed, risk of heat exhaustion and heat cramps is high. Continuous activity might trigger heatstroke.Realize that the values for the heat index are set for shaded places and light winds. If directly exposed to the sun, the heat index could rise by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', comes about by integrating the temperature readings with the humidity levels. An individual's temperature experience can be influenced by extra factors, including metabolic differences, activity levels, and clothing. It is noteworthy that being in direct sunlight can enhance the weather's impact, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important 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 Williamson, the average relative humidity in August is 80%.Rainfall
In Williamson, in August, during 12.1 rainfall days, 1.57" (40mm) of precipitation is typically accumulated. Throughout the year, there are 121.4 rainfall days, and 14.72" (374mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In August, the average length of the day is 13h and 38min.On the first day of the month, sunrise is at 6:00 am and sunset at 8:10 pm. On the last day of August, in Williamson, sunrise is at 6:27 am and sunset at 7:30 pm CDT.
Sunshine
In Williamson, the average sunshine in August 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 health risk from unsafe exposure to UV radiation for the average person.Note: A maximum UV index of 6 in August translates into the following recommendations:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. Avoid direct sunlight between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Keep in mind that shade structures may not provide complete protection. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Williamson, IL
- Average high temperature in August: 82.9°F
The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (35.6°F).
- Average low temperature in August: 65.5°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in August
Williamson, IL
- Average pressure in August: 29.98"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in August
Williamson, IL
- Average wind speed in August: 5.9mph
The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).
Average humidity in August
Williamson, IL
- Average humidity in August: 80%
The month with the highest relative humidity is July (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall in August
Williamson, IL
- Average rainfall in August: 1.57"
The wettest month (with the highest rainfall) is June (1.89").
The driest month (with the least rainfall) is February (0.67").
Average rainfall days in August
Williamson, IL
- Average rainfall days in August: 12.1 days
The month with the highest number of rainy days is July (14 days).
The month with the least rainy days is January (5.8 days).
Average snowfall in August
Williamson, IL
- Average snowfall in August: 0"
The month with the highest snowfall is December (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in August
Williamson, IL
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is January (6.3 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
Williamson, IL
- Average daylight in August: 13h and 36min
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: 9h and 54min
The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in August
Williamson, IL
- Average sunshine days in August: 15.3 days
The month with the most sunshine days is January (20.9 days).
The month with the least sunshine days is July (12.5 days).
Average UV index in August
Williamson, 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
Williamson, IL
- Average cloud cover in August: 29
The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).
Average visibility in August
Williamson, IL
- Average visibility in August: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).





