September weather forecastDecatur, GA
September
Weather in September
September, the first month of the autumn in Decatur, is still a warm month, with temperature in the range of an average low of 65.5°F (18.6°C) and an average high of 84.2°F (29°C).Temperature
Decatur's weather in September, with an average high-temperature of a moderately hot 84.2°F (29°C), subtly shifts from August's 89.2°F (31.8°C). The average nighttime temperature lowers to an enjoyable 65.5°F (18.6°C) throughout September.Heat index
The heat index value for September is calculated to be a hot 91.4°F (33°C). Special measures are necessary to avoid heat cramps and heat exhaustion. Persistent activity could result in heatstroke.Heat index readings emphasize conditions of light breezes and shaded spots. A direct sunlight exposure may boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is derived by integrating air temperature with the existing relative humidity to express the perceived warmth. Elements such as metabolic variations, pregnancy, and physical exertion can shape one's weather perception. Understand that direct sun rays can influence the weather's impact, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children frequently underestimate the necessity to rest and hydrate. Thirst is a late sign of dehydration - thus, it is vital to stay hydrated, particularly during lengthy physical exercises.
Humidity
In Decatur, the average relative humidity in September is 70%.Rainfall
The month with the least rainfall is September, when the rain falls for 8.6 days and typically collects 0.55" (14mm) of precipitation.Snowfall
April through November are months without snowfall.Daylight
In September, the average length of the day is 12h and 22min.On the first day of September, sunrise is at 7:11 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 7:31 am and sunset at 7:22 pm EDT.
Sunshine
In September, the average sunshine is 8.7h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index of 5 during September leads to these instructions:
Ensure safety - Sun damage prevention is strongly urged. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Decatur, GA
- Average high temperature in September: 84.2°F
The warmest month (with the highest average high temperature) is July (90.7°F).
The month with the lowest average high temperature is January (50.5°F).
- Average low temperature in September: 65.5°F
The month with the highest average low temperature is July (71.6°F).
The coldest month (with the lowest average low temperature) is January (34.9°F).
Average pressure in September
Decatur, GA
- 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 (29.99"Hg).
Average wind speed in September
Decatur, GA
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is January (8mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).
Average humidity in September
Decatur, GA
- Average humidity in September: 70%
The month with the highest relative humidity is December (77%).
The months with the lowest relative humidity are July and August (69%).
Average rainfall in September
Decatur, GA
- Average rainfall in September: 0.55"
The wettest month (with the highest rainfall) is August (2.32").
The driest month (with the least rainfall) is September (0.55").
Average rainfall days in September
Decatur, GA
- Average rainfall days in September: 8.6 days
The month with the highest number of rainy days is August (17.1 days).
The month with the least rainy days is November (6.9 days).
Average snowfall in September
Decatur, GA
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.2").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").
Average snowfall days in September
Decatur, GA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Decatur, GA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 8h and 42min
The months with the most sunshine are June and July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).
Average sunshine days in September
Decatur, GA
- Average sunshine days in September: 19.2 days
The month with the most sunshine days is October (22.6 days).
The month with the least sunshine days is July (10.9 days).
Average UV index in September
Decatur, GA
- Average UV index in September: 5
The month with the highest UV index is August (UV index 7).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Decatur, GA
- Average cloud cover in September: 30
The month with the most cloud cover is December (Cloud cover 46).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in September
Decatur, GA
- 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).
