September weather forecastKarnak, IL
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Karnak, Illinois, with an average temperature varying between 81.1°F (27.3°C) and 60.6°F (15.9°C).Temperature
September witnesses a gentle descent in average high-temperature, descending from August's hot 86.5°F (30.3°C) to a moderately hot 81.1°F (27.3°C). Karnak reports an average nighttime low-temperature of 60.6°F (15.9°C) in September.Heat index
September's heat index is appraised at a hot 86°F (30°C). Uninterrupted activity during exposure could lead to a sense of exhaustion, possibly causing heat cramps.Take into consideration that the heat index values are calculated for shade and light wind conditions. A rise in the heat index by 15 Fahrenheit (8 Celsius) degrees may result from direct sunlight exposure.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is the result of factoring in humidity to the air temperature, indicating perceived warmth. Metabolic differences, pregnancy status, and the level of physical activity are additional factors influencing an individual's weather perception. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values remain especially vital for babies and toddlers. 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.
Humidity
In Karnak, Illinois, the average relative humidity in September is 73%.Rainfall
The month with the least rainfall is September, when the rain falls for 8.3 days and typically collects 0.47" (12mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In Karnak, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:27 am and sunset at 7:24 pm. On the last day of September, in Karnak, sunrise is at 6:51 am and sunset at 6:40 pm CDT.
Sunshine
In Karnak, the average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: In September, a regular UV index of 5 translates into these guidelines:
Act with care - The need to guard against sun damage is communicated. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Karnak, IL
- Average high temperature in September: 81.1°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.1°F).
- Average low temperature in September: 60.6°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (27°F).
Average pressure in September
Karnak, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Karnak, IL
- Average wind speed in September: 6.3mph
The windiest months (with the highest average wind speed) are January and February (9mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
Karnak, IL
- Average humidity in September: 73%
The months with the highest relative humidity are March and May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Karnak, IL
- Average rainfall in September: 0.47"
The wettest month (with the highest rainfall) is June (1.5").
The driest month (with the least rainfall) is September (0.47").
Average rainfall days in September
Karnak, IL
- Average rainfall days in September: 8.3 days
The month with the highest number of rainy days is July (13.1 days).
The months with the least rainy days are January, February and December (7.3 days).
Average snowfall in September
Karnak, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.67").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Karnak, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Karnak, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 9h and 24min
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 September
Karnak, IL
- Average sunshine days in September: 19.1 days
The month with the most sunshine days is October (21.5 days).
The month with the least sunshine days is June (14.8 days).
Average UV index in September
Karnak, IL
- Average UV index in September: 5
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 and December (UV index 2).
Average cloud cover in September
Karnak, IL
- Average cloud cover in September: 28
The months with the most cloud cover are January and February (Cloud cover 51).
The month with the least cloud cover is September (Cloud cover 28).
Average visibility in September
Karnak, IL
- Average visibility in September: 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).
