Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Entering September, the average high-temperature is recorded at a still tropical 86.9°F (30.5°C), exhibiting a minimal shift from August's 91.6°F (33.1°C). Knoxville's temperature in September lowers to a consistent average of 66.9°F (19.4°C) during the nights.Heat index
The heat index in September is evaluated at a torrid 98.6°F (37°C). Incorporate additional safety actions, heat cramps and heat exhaustion are possible. Long-term activity may induce heatstroke.Observations indicate that the heat index values are for shady locations with light wind. Heat index values can rise by 15 Fahrenheit (8 Celsius) degrees when in direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'real feel', provides an understanding of perceived warmth by combining temperature and relative humidity. The impact of weather is individual, with diverse individuals experiencing it differently due to variations in body mass, height, and activity levels. 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 meaningful for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it's vital to remain hydrated, particularly during prolonged physical activities.
To combat high temperatures, the human body perspires and relies on sweat evaporation for cooling. Elevated relative humidity disrupts typical body cooling by reducing the evaporation rate, consequently decreasing the body's cooling rate and enhancing the feeling of heat. Increasing body temperatures can be a precursor to dehydration if the body can't shed the extra heat.
Humidity
The average relative humidity in September is 72%.Rainfall
In Knoxville, in September, it is raining for 13.5 days, with typically 2.32" (59mm) of accumulated precipitation. Throughout the year, there are 166.5 rainfall days, and 39.41" (1001mm) of precipitation is accumulated.Snowfall
March through November are months without snowfall.Daylight
In Knoxville, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:26 am and sunset at 7:15 pm. On the last day of September, sunrise is at 6:45 am and sunset at 6:36 pm CDT.
Sunshine
The average sunshine in September is 9.1h.UV index
The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 6 in September interprets into the following recommendations:
Shun overexposure. Protection from sun ravages is indispensable. The Sun's UV radiation is most intense from 10 a.m. to 4 p.m. Try to avoid direct sun exposure during these hours. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it hot during September?
What is the average humidity in September in Knoxville?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does Knoxville have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Knoxville have in September?
What is the UV index reading in September?
Average temperature in September
Knoxville, AL
- Average high temperature in September: 86.9°F
The warmest month (with the highest average high temperature) is July (91.9°F).
The month with the lowest average high temperature is January (52.9°F).
- Average low temperature in September: 66.9°F
The months with the highest average low temperature are July and August (71.6°F).
The coldest month (with the lowest average low temperature) is January (37.4°F).
Average pressure in September
Knoxville, AL
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).
Average wind speed in September
Knoxville, AL
- Average wind speed in September: 5.1mph
The windiest month (with the highest average wind speed) is February (7.2mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).
Average humidity in September
Knoxville, AL
- Average humidity in September: 72%
The month with the highest relative humidity is December (80%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Knoxville, AL
- Average rainfall in September: 2.32"
The wettest month (with the highest rainfall) is April (4.29").
The driest month (with the least rainfall) is October (2.28").
Average rainfall days in September
Knoxville, AL
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is July (20.6 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Knoxville, AL
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.55").
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0").
Average snowfall days in September
Knoxville, AL
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (0.8 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Knoxville, AL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 9h and 1min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).
Average sunshine days in September
Knoxville, AL
- Average sunshine days in September: 14.8 days
The month with the most sunshine days is October (20.5 days).
The month with the least sunshine days is July (8.8 days).
Average UV index in September
Knoxville, AL
- Average UV index in September: 6
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, February and December (UV index 3).
Average cloud cover in September
Knoxville, AL
- Average cloud cover in September: 29
The months with the most cloud cover are February and December (Cloud cover 48).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in September
Knoxville, AL
- 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).
Knoxville, Alabama, USA
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