September weather forecastFort Smith, AR
September
Weather in September
Fort Smith welcomes fall in September. The months' air is filled with changing leaves, cooler temperatures and increasingly shorter days. The transition towards autumn feels seamless, providing a comfortable ambiance to residents. However, September still holds on to the summer heat, indicated by the temperature margin set from 63°F (17.2°C) to 85.1°F (29.5°C). This month heralds the disappearance of sultry summer days.Temperature
The beginning of September in Fort Smith brings a slight decrease in the average high-temperature, transitioning from a tropical 91.9°F (33.3°C) in August to a warm 85.1°F (29.5°C). Despite the high peak temperatures, Fort Smith witnesses an average nighttime cooling to an enjoyable 63°F (17.2°C) in September.Heat index
September's mean heat index is evaluated at a tropical 93.2°F (34°C). Implement additional preventive actions, heat cramps and heat exhaustion are potential hazards. Heatstroke could follow prolonged activity.From a standpoint of the heat index, values pertain to shaded conditions and mild breezes. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', binds temperature metrics with humidity values to give a sense of the actual warmth. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Young ones often disregard the necessity to rest and hydrate. Thirst usually indicates advanced dehydration - hence, it is key to stay hydrated, particularly during ongoing physical activities.
Humidity
In September, the average relative humidity in Fort Smith is 71%.Rainfall
In September, the rain falls for 10.6 days. Throughout September, 1.93" (49mm) of precipitation is accumulated. Throughout the year, in Fort Smith, there are 131.9 rainfall days, and 25.51" (648mm) of precipitation is accumulated.Snowfall
April through November are months without snowfall.Daylight
The average length of the day in September in Fort Smith is 12h and 23min.On the first day of September in Fort Smith, sunrise is at 6:50 am and sunset at 7:44 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 7:02 pm CDT.
Sunshine
In Fort Smith, the average sunshine in September is 9.6h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.Note: In September, the maximum UV index of 5 translates into these guidelines:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Fort Smith, AR
- Average high temperature in September: 85.1°F
The warmest month (with the highest average high temperature) is July (93.4°F).
The month with the lowest average high temperature is January (48°F).
- Average low temperature in September: 63°F
The month with the highest average low temperature is July (70.7°F).
The coldest month (with the lowest average low temperature) is January (31.5°F).
Average pressure in September
Fort Smith, AR
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Fort Smith, AR
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).
Average humidity in September
Fort Smith, AR
- Average humidity in September: 71%
The months with the highest relative humidity are March and May (77%).
The months with the lowest relative humidity are July and August (70%).
Average rainfall in September
Fort Smith, AR
- Average rainfall in September: 1.93"
The wettest month (with the highest rainfall) is May (3.43").
The driest month (with the least rainfall) is February (1.34").
Average rainfall days in September
Fort Smith, AR
- Average rainfall days in September: 10.6 days
The month with the highest number of rainy days is April (14 days).
The month with the least rainy days is November (7.6 days).
Average snowfall in September
Fort Smith, AR
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.31").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").
Average snowfall days in September
Fort Smith, AR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.7 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
Fort Smith, AR
- 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: 9h and 36min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The months with the least sunshine are January and December (Average sunshine: 5h and 30min).
Average sunshine days in September
Fort Smith, AR
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is January (21.4 days).
The month with the least sunshine days is April (14.2 days).
Average UV index in September
Fort Smith, AR
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 7).
The month with the lowest UV index is December (UV index 2).
Average cloud cover in September
Fort Smith, AR
- Average cloud cover in September: 26
The month with the most cloud cover is February (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 24).
Average visibility in September
Fort Smith, AR
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
