September weather forecast
Sumter Junction, SC

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Weather in September

September, the first month of the autumn in Sumter Junction, is still a warm month, with an average temperature fluctuating between 83.7°F (28.7°C) and 66.6°F (19.2°C).

Temperature

September's advent presents an average high-temperature of a warm 83.7°F (28.7°C), indicating a slight variation from the conditions of the previous month. Sumter Junction's temperature drops to an average low of 66.6°F (19.2°C) during the nights of September.

Heat index

For September, the heat index is estimated at a hot 91.4°F (33°C). Ensure additional precautions, heat exhaustion and heat cramps may be expected. Heatstroke could occur from sustained activity.
It is crucial to understand that heat index figures are for shade and gentle wind conditions. With exposure to direct sunshine, the heat index could climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', provides an understanding of perceived warmth by combining temperature and relative humidity. Metabolic differences, pregnancy status, and the level of physical activity are additional factors influencing an individual's weather perception. Take note that direct exposure to the sun can increase the felt temperature, possibly adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are of high significance for children. Young children typically face greater hazards than adults because they do not sweat as much. Their larger skin surface in comparison to their little bodies and the high heat production from their active nature compounds their vulnerability.

Humidity

In September, the average relative humidity is 75%.

Rainfall

In Sumter Junction, South Carolina, in September, it is raining for 14.1 days, with typically 2.48" (63mm) of accumulated precipitation. Throughout the year, there are 161.8 rainfall days, and 33.35" (847mm) of precipitation is accumulated.

Snowfall

In Sumter Junction, snow does not fall in April through October.

Daylight

In Sumter Junction, the average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:56 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:16 am and sunset at 7:07 pm EDT.

Sunshine

In Sumter Junction, South Carolina, the average sunshine in September is 8.7h.

UV index

In Sumter Junction, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for the ordinary person.
Note: A maximum high daily UV index of 6 during September translates into the following directions:
Implement preventive steps and embrace sun safety standards. Protection from skin and eye distress is compulsory. Limit your direct sun exposure, especially between 10 a.m. and 4 p.m., when UV radiation is strongest. Shade structures might not provide complete sun protection. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Updated: Jul 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot does it get in September?

During September, Sumter Junction experiences an average high-temperature of 83.7°F (28.7°C) and a low-temperature of 66.6°F (19.2°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, in September is estimated at 91.4°F (33°C).

What is the average humidity in September?

In September, the average relative humidity is 75%.

How much does it rain in September?

In Sumter Junction, in September, it is raining for 14.1 days, with typically 2.48" (63mm) of accumulated precipitation.

When it does not snow?

April through October are months without snowfall.

How many hours of daylight does Sumter Junction have in September?

The average day length in September in Sumter Junction is 12h and 22min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:56 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 7:07 pm EDT.

How many hours of sunshine does Sumter Junction have in September?

In Sumter Junction, the average sunshine duration in September is 8.7h.

How high is the UV index in September?

In September, the average daily maximum UV index is 6. A UV Index value of 6 to 7 symbolizes a high health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Sumter Junction, SC

Average temperature in September - Sumter Junction, SC
  • Average high temperature in September: 83.7°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 (52.9°F).

  • Average low temperature in September: 66.6°F

The month with the highest average low temperature is July (72.9°F).
The coldest month (with the lowest average low temperature) is January (38.1°F).

Average pressure in September
Sumter Junction, SC

Average pressure in September - Sumter Junction, SC
  • Average pressure in September: 30.01"Hg

The months with the highest atmospheric pressure are January, November and December (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).

Average wind speed in September
Sumter Junction, SC

Average wind speed in September - Sumter Junction, SC
  • Average wind speed in September: 6.3mph

The windiest months (with the highest average wind speed) are February and April (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).

Average humidity in September
Sumter Junction, SC

Average humidity in September - Sumter Junction, SC
  • Average humidity in September: 75%

The month with the highest relative humidity is May (76%).
The months with the lowest relative humidity are January and November (70%).

Average rainfall in September
Sumter Junction, SC

Average rainfall in September - Sumter Junction, SC
  • Average rainfall in September: 2.48"

The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (1.89").

Average rainfall days in September
Sumter Junction, SC

Average rainfall days in September - Sumter Junction, SC
  • Average rainfall days in September: 14.1 days

The month with the highest number of rainy days is July (20.1 days).
The month with the least rainy days is October (8.5 days).

Average snowfall in September
Sumter Junction, SC

Average snowfall in September - Sumter Junction, SC
  • Average snowfall in September: 0"

The month with the highest snowfall is February (0.55").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Sumter Junction, SC

Average snowfall days in September - Sumter Junction, SC
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (0.6 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
Sumter Junction, SC

Average daylight in September / Average sunshine in September - Sumter Junction, SC
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).

Average sunshine days in September
Sumter Junction, SC

Average sunshine days in September - Sumter Junction, SC
  • Average sunshine days in September: 13.5 days

The month with the most sunshine days is October (20.8 days).
The month with the least sunshine days is July (8.8 days).

Average UV index in September
Sumter Junction, SC

Average UV index in September - Sumter Junction, SC
  • Average UV index in September: 6

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 3).

Average cloud cover in September
Sumter Junction, SC

Average cloud cover in September - Sumter Junction, SC
  • Average cloud cover in September: 33

The months with the most cloud cover are February and December (Cloud cover 42).
The month with the least cloud cover is October (Cloud cover 29).

Average visibility in September
Sumter Junction, SC

Average visibility in September - Sumter Junction, SC
  • 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).

Sumter Junction, South Carolina, USA

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