September weather forecast
Knoxville, TN

The scenic scape of the little town of Knoxville in Tennessee
The scenic scape of the little town of Knoxville in Tennessee

Weather in September

September, the first month of the autumn in Knoxville, is still a warm month, with an average temperature ranging between max 82.2°F (27.9°C) and min 59.9°F (15.5°C).

Temperature

In Knoxville, the average high-temperature in September slightly decreases from a hot 88.2°F (31.2°C) in August to a moderately hot 82.2°F (27.9°C). The average low-temperature, in Knoxville, is 59.9°F (15.5°C).

Heat index

In September, the average heat index is estimated at a tropical 87.8°F (31°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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 'feels like', 'apparent temperature', 'real feel', or 'felt air temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. Additional factors like activity, wind, metabolic differences, and differences in body mass, height, and shape affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

In September, the average relative humidity is 72%.

Rainfall

September is the month with the least rainfall. Rain falls for 11.3 days and accumulates 1.5" (38mm) of precipitation.

Snowfall

May through October are months without snowfall.

Daylight

The average length of the day in September is 12h and 23min.
On the first day of September, sunrise is at 7:07 am and sunset at 8:03 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 7:21 pm EDT.

Sunshine

The average sunshine in September is 8.6h.

UV index

The average daily maximum UV index in September in Knoxville, Tennessee, is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The average daily UV index of 5 in September transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
[Resources]

FAQ

What is the temperature in September in Knoxville?

The average high-temperature, in September, in Knoxville, Tennessee, is 82.2°F (27.9°C), while the average low-temperature is 59.9°F (15.5°C). in September, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines relative humidity and air temperature, is estimated at 87.8°F (31°C).

What is the average humidity in September in Knoxville?

The average relative humidity in September in Knoxville is 72%.

What is the driest month in Knoxville?

September is the month with the least rainfall. Rain falls for 11.3 days and accumulates 1.5" (38mm) of precipitation.

How much does it rain in Knoxville in September?

In Knoxville, during September, the rain falls for 11.3 days and regularly aggregates up to 1.5" (38mm) of precipitation.

When it does not snow in Knoxville?

May through October are months without snowfall.

What is the average length of the day in September in Knoxville?

In Knoxville, Tennessee, the average day length in September is 12h and 23min.

When are sunrise and sunset in September in Knoxville?

In September, on the first day of the month, sunrise is at 7:07 am and sunset at 8:03 pm. On the last day of the month, in Knoxville, sunrise is at 7:30 am and sunset at 7:21 pm EDT.

How long on average sun shines in September in Knoxville?

The average sunshine duration in September in Knoxville, Tennessee, is 8.6h.

How high is the UV index in September in Knoxville?

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Knoxville, TN

Average temperature in September - Knoxville, TN
  • Average high temperature in September: 82.2°F

The warmest month (with the highest average high temperature) is July (88.9°F).
The month with the lowest average high temperature is January (44.8°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (29.3°F).

[Resources]

Average pressure in September
Knoxville, TN

Average pressure in September - Knoxville, TN
  • Average pressure in September: 30.04"Hg

The months with the highest atmospheric pressure are January and November (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).

[Resources]

Average wind speed in September
Knoxville, TN

Average wind speed in September - Knoxville, TN
  • Average wind speed in September: 4mph

The windiest month (with the highest average wind speed) is April (6mph).
The calmest month (with the lowest average wind speed) is August (3.8mph).

[Resources]

Average humidity in September
Knoxville, TN

Average humidity in September - Knoxville, TN
  • Average humidity in September: 72%

The months with the highest relative humidity are February and December (78%).
The month with the lowest relative humidity is August (70%).

[Resources]

Average rainfall in September
Knoxville, TN

Average rainfall in September - Knoxville, TN
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is February (3.66").
The driest month (with the least rainfall) is September (1.5").

[Resources]

Average rainfall days in September
Knoxville, TN

Average rainfall days in September - Knoxville, TN
  • Average rainfall days in September: 11.3 days

The month with the highest number of rainy days is July (16.2 days).
The month with the least rainy days is November (8.4 days).

[Resources]

Average snowfall in September
Knoxville, TN

Average snowfall in September - Knoxville, TN
  • Average snowfall in September: 0"

The month with the highest snowfall is February (1.57").
The months with the least snowfall are May, June, July, August, September and October (0").

[Resources]

Average snowfall days in September
Knoxville, TN

Average snowfall days in September - Knoxville, TN
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (3.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

[Resources]

Average daylight in September /
Average sunshine in September
Knoxville, TN

Average daylight in September / Average sunshine in September - Knoxville, TN
  • Average daylight in September: 12h and 23min

The month with the longest days is June (Average daylight: 14h and 34min).
The month with the shortest days is December (Average daylight: 9h and 46min).

  • Average sunshine in September: 8h and 36min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).

[Resources]

Average sunshine days in September
Knoxville, TN

Average sunshine days in September - Knoxville, TN
  • Average sunshine days in September: 17.4 days

The month with the most sunshine days is October (20.5 days).
The month with the least sunshine days is July (12.9 days).

[Resources]

Average UV index in September
Knoxville, TN

Average UV index in September - Knoxville, TN
  • 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).

[Resources]

Average cloud cover in September
Knoxville, TN

Average cloud cover in September - Knoxville, TN
  • Average cloud cover in September: 30

The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is June (Cloud cover 28).

[Resources]

Average visibility in September
Knoxville, TN

Average visibility in September - Knoxville, TN
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

[Resources]

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location
* you will be automatically redirected to the weather forecast for your location