September weather forecastDecatur, TN
September
Weather in September
The first month of the autumn, September, is still a warm month in Decatur, Tennessee, with temperature in the range of an average low of 59.9°F (15.5°C) and an average high of 81°F (27.2°C).Temperature
September sees a slight reduction in average high-temperature, with a shift from a hot 86.9°F (30.5°C) in August to a moderately hot 81°F (27.2°C). Decatur's temperature lowers to a mean of 59.9°F (15.5°C) during the nights in September.Heat index
September's heat index is estimated at a tropical 86°F (30°C). With constant exposure and activity, a state of weariness might ensue, leading to potential heat cramps.Evaluating the heat index requires understanding its values in the shade and with gentle winds. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', determines the feeling of heat when you account for the relative humidity. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. Keep aware, the sun, when shining directly, can intensify the heat experience, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Young ones are generally more prone to risk than adults due to their reduced ability to sweat. Their large skin surface area relative to their diminutive bodies and elevated heat production from their activities further enhance this risk.
Humidity
In Decatur, Tennessee, the average relative humidity in September is 76%.Rainfall
September is the month with the least rainfall. Rain falls for 11.7 days and accumulates 2.32" (59mm) of precipitation.Snowfall
In Decatur, Tennessee, snow does not fall in May through October.Daylight
In Decatur, the average length of the day in September is 12h and 23min.On the first day of the month, sunrise is at 7:11 am and sunset at 8:05 pm. On the last day of September, sunrise is at 7:33 am and sunset at 7:23 pm EDT.
Sunshine
In Decatur, the average sunshine in September is 8.5h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for average individuals.Note: In September, an average UV index of 5 transforms into the following instructions:
Put precautions into practice - Guidance to elude sunburn is provided. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Decatur, TN
- Average high temperature in September: 81°F
The warmest month (with the highest average high temperature) is July (87.6°F).
The month with the lowest average high temperature is January (45.5°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in September
Decatur, TN
- Average pressure in September: 30.03"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).
Average wind speed in September
Decatur, TN
- Average wind speed in September: 4.2mph
The windiest months (with the highest average wind speed) are February, March and April (6.5mph).
The calmest months (with the lowest average wind speed) are July and August (3.9mph).
Average humidity in September
Decatur, TN
- Average humidity in September: 76%
The month with the highest relative humidity is December (80%).
The months with the lowest relative humidity are June, August, October and November (75%).
Average rainfall in September
Decatur, TN
- Average rainfall in September: 2.32"
The wettest months (with the highest rainfall) are July and December (4.29").
The driest month (with the least rainfall) is September (2.32").
Average rainfall days in September
Decatur, TN
- Average rainfall days in September: 11.7 days
The month with the highest number of rainy days is July (18.3 days).
The month with the least rainy days is November (9.5 days).
Average snowfall in September
Decatur, TN
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.02").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Decatur, TN
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.8 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
Decatur, TN
- Average daylight in September: 12h and 24min
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: 8h and 30min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The month with the least sunshine is December (Average sunshine: 5h and 0min).
Average sunshine days in September
Decatur, TN
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is October (18.6 days).
The month with the least sunshine days is July (10.2 days).
Average UV index in September
Decatur, 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).
Average cloud cover in September
Decatur, TN
- Average cloud cover in September: 31
The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 30).
Average visibility in September
Decatur, TN
- Average visibility in September: 6mi
The months with the highest visibility are February, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and March (5mi).
