Contents
- Weather in August
- Frequently asked questions
- Average temperature in August
- Average pressure in August
- Average wind speed in August
- Average humidity in August
- Average rainfall in August
- Average rainfall days in August
- Average snowfall in August
- Average snowfall days in August
- Average daylight in August
- Average sunshine in August
- Average sunshine days in August
- Average UV index in August
- Average cloud cover in August
- Average visibility in August
Weather in August
Temperature
Saint Johns's transition from July to August introduces an average high-temperature of a warm 85.5°F (29.7°C), marking an insignificant variation from the 87.3°F (30.7°C). Throughout August, the average low-temperature records at a comfortable 66°F (18.9°C).Heat index
The heat index in August is calculated to be a torrid 96.8°F (36°C). Incorporate special precautions, risk of heat exhaustion and heat cramps is substantial. Sustained activity could cause heatstroke.Keep in mind the heat index values are meant for areas in shade and with light wind. 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 calculated temperature value of how hot it feels when the moisture in the air is factored in. A person's impression of weather can be affected by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Being aware that direct sunlight can impact the felt heat might mean an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Young ones often underestimate the need for rest and rehydration. Thirst appears late in dehydration - hence, it is important to keep hydrated, particularly during prolonged physical activities.
In response to overheating, the human body perspires to cool down, mainly through the evaporation of sweat. When relative humidity is heightened, it slows the rate of evaporation, thereby decreasing the body's ability to shed heat and creating a sensation of overheating. Heat-related disorders may develop if heat gain in the body overshadows its cooling capacity, leading to elevated temperatures.
Humidity
In August, the average relative humidity is 77%.Rainfall
In Saint Johns, in August, it is raining for 14 days, with typically 2.8" (71mm) of accumulated precipitation. In Saint Johns, during the entire year, the rain falls for 147.6 days and collects up to 29.17" (741mm) of precipitation.Snowfall
In Saint Johns, snow does not fall in May through October.Daylight
In August, the average length of the day in Saint Johns is 13h and 35min.On the first day of the month, sunrise is at 6:00 am and sunset at 8:05 pm. On the last day of August, sunrise is at 6:26 am and sunset at 7:27 pm CDT.
Sunshine
The average sunshine in August is 10.1h.UV index
June through August, with an average maximum UV index of 6, are months with the highest UV index in Saint Johns. A UV Index reading of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The daily maximum UV index of 6 in August interprets into the following advice:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Remember that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. Make an effort to avoid direct sun exposure during these hours. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is August?
What is the average humidity in August?
How many days does it rain in August?
When it does not snow?
How many hours of daylight does Saint Johns have in August?
When is the sunrise / sunset in August?
How many hours of sunshine does Saint Johns have in August?
When is the highest UV index?
How high is the UV index in August?
Average temperature in August
Saint Johns, IL
- Average high temperature in August: 85.5°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (38.8°F).
- Average low temperature in August: 66°F
The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).
Average pressure in August
Saint Johns, 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 (29.93"Hg).
Average wind speed in August
Saint Johns, IL
- Average wind speed in August: 5.8mph
The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).
Average humidity in August
Saint Johns, 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
Saint Johns, IL
- Average rainfall in August: 2.8"
The wettest month (with the highest rainfall) is April (3.58").
The driest month (with the least rainfall) is January (1.5").
Average rainfall days in August
Saint Johns, IL
- Average rainfall days in August: 14 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is December (8.2 days).
Average snowfall in August
Saint Johns, IL
- Average snowfall in August: 0"
The month with the highest snowfall is February (1.5").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in August
Saint Johns, IL
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is January (5.4 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
Saint Johns, IL
- Average daylight in August: 13h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- 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
Saint Johns, IL
- Average sunshine days in August: 14.7 days
The months with the most sunshine days are October and November (19.5 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in August
Saint Johns, 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
Saint Johns, IL
- Average cloud cover in August: 29
The months with the most cloud cover are January and February (Cloud cover 50).
The month with the least cloud cover is June (Cloud cover 28).
Average visibility in August
Saint Johns, 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).
Saint Johns, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location