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
The arrival of September corresponds with a light shift in temperature, down from a tropical 90.7°F (32.6°C) in August to a warm 83.7°F (28.7°C). Marked by a significant temperature drop from daytime highs, the average nighttime temperature lowers to a refreshing 61.7°F (16.5°C) throughout September.Heat index
For September, the heat index is estimated at a tropical 91.4°F (33°C). Exercise heightened safety, heat cramps and heat exhaustion are probable. Persistent activity may provoke heatstroke.Keep in mind the heat index values are meant for areas in shade and with light wind. With direct sunlight, the heat index could increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', ties air temperature with relative humidity to produce the perceived temperature sensation. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Typically, children face more danger than adults as they usually perspire less. Their larger skin surface relative to their small bodies and increased heat output from their activities enhance their risk.
Humidity
In Knoxville, the average relative humidity in September is 73%.Rainfall
July and September are months with the least rain when the rain falls for 11.7 days and typically aggregates up to 2.36" (60mm) of rain.Snowfall
In Knoxville, snow does not fall in April through October.Daylight
In Knoxville, the average length of the day in September is 12h and 23min.On the first day of the month, sunrise is at 6:46 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:08 am and sunset at 6:58 pm CDT.
Sunshine
In September, the average sunshine is 9.3h.UV index
In Knoxville, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Exercise prevention - Protecting skin and eyes from harm is required. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in September?
What is the average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow in Knoxville?
What is the average length of the day in September in Knoxville?
When is the sunrise / sunset in September?
How many hours of sunshine does Knoxville have in September?
How high is the UV index in September in Knoxville?
Average temperature in September
Knoxville, AR
- Average high temperature in September: 83.7°F
The warmest month (with the highest average high temperature) is July (91.4°F).
The month with the lowest average high temperature is January (46.9°F).
- Average low temperature in September: 61.7°F
The month with the highest average low temperature is July (68.9°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in September
Knoxville, AR
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Knoxville, AR
- Average wind speed in September: 4.4mph
The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest months (with the lowest average wind speed) are July and August (4.2mph).
Average humidity in September
Knoxville, AR
- Average humidity in September: 73%
The months with the highest relative humidity are March and May (79%).
The months with the lowest relative humidity are July and August (72%).
Average rainfall in September
Knoxville, AR
- Average rainfall in September: 2.36"
The wettest months (with the highest rainfall) are April and May (4.41").
The driest months (with the least rainfall) are July and September (2.36").
Average rainfall days in September
Knoxville, AR
- Average rainfall days in September: 11.7 days
The month with the highest number of rainy days is May (15.5 days).
The month with the least rainy days is November (9 days).
Average snowfall in September
Knoxville, AR
- Average snowfall in September: 0"
The months with the highest snowfall are January and February (0.79").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Knoxville, AR
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (1.5 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, AR
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 5h and 24min).
Average sunshine days in September
Knoxville, AR
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is January (20.3 days).
The month with the least sunshine days is May (13.2 days).
Average UV index in September
Knoxville, AR
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Knoxville, AR
- Average cloud cover in September: 30
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Knoxville, AR
- Average visibility in September: 6mi
The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April, May, November and December (5mi).
Knoxville, Arkansas, USA
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