August weather forecastGrafton, IL
August
Weather in August
The last month of the summer, August, is another warm month in Grafton, Illinois, with an average temperature varying between 66.4°F (19.1°C) and 84.9°F (29.4°C).Temperature
Entering August, the average high-temperature is recorded at a moderately hot 84.9°F (29.4°C), exhibiting a minimal shift from July's 86.4°F (30.2°C). During the month of August, an average temperature of 66.4°F (19.1°C) is noted during the nights.Heat index
August's mean heat index is evaluated at a torrid 95°F (35°C). Exercise special caution, heat exhaustion and heat cramps are probable. Prolonged activity may induce heatstroke.Heat index evaluations are typically in the context of light winds and shaded environments. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. Depending on the activity and the individual's heat perception, which may vary due to factors including wind, clothing, and metabolic variations, this effect remains subjective. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children often fail to understand the importance of rest and rehydration. Thirst is a late manifestation of dehydration - hence, it is crucial to stay hydrated, especially during ongoing physical activities.
When temperatures rise, the human body turns to perspiration, using the cooling power of evaporating sweat. Greater relative humidity lessens the rate of evaporation, thus decreasing the body's heat dispersal, which gives rise to a sensation of overheating. Overheating can ensue when the body accumulates more heat than it can release, and dehydration severity may vary.
Humidity
The average relative humidity in August is 77%.Rainfall
In August, the rain falls for 13.6 days. Throughout August, 2.99" (76mm) of precipitation is accumulated. In Grafton, during the entire year, the rain falls for 138.8 days and collects up to 27.6" (701mm) of precipitation.Snowfall
In Grafton, Illinois, snow does not fall in April through October.Daylight
The average length of the day in August in Grafton is 13h and 38min.On the first day of August in Grafton, sunrise is at 6:03 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 6:30 am and sunset at 7:33 pm CDT.
Sunshine
In August, the average sunshine is 10.2h.UV index
The months with the highest UV index in Grafton, Illinois, are May through August, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for the average person.Note: The maximum UV index of 6 during August leads to these instructions:
Avoid overexposure. Fair-skinned individuals can burn in under 20 minutes. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Grafton, IL
- Average high temperature in August: 84.9°F
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (36.1°F).
- Average low temperature in August: 66.4°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).
Average pressure in August
Grafton, IL
- Average pressure in August: 29.97"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
Grafton, IL
- Average wind speed in August: 5.7mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in August
Grafton, IL
- Average humidity in August: 77%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in August
Grafton, IL
- Average rainfall in August: 2.99"
The wettest month (with the highest rainfall) is May (3.35").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in August
Grafton, IL
- Average rainfall days in August: 13.6 days
The month with the highest number of rainy days is July (16.3 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in August
Grafton, IL
- Average snowfall in August: 0"
The months with the highest snowfall are January and February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in August
Grafton, IL
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is January (5.7 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
Grafton, 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: 10h and 12min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 36min).
Average sunshine days in August
Grafton, IL
- Average sunshine days in August: 14.3 days
The month with the most sunshine days is December (19.8 days).
The month with the least sunshine days is June (11.2 days).
Average UV index in August
Grafton, IL
- 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
Grafton, IL
- Average cloud cover in August: 28
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in August
Grafton, 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).
