September weather forecast
Chapel Hill, NC

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Red flowers and green trees around the Old Well at the iconic UNC in Chapel Hill, North Carolina
Red flowers and green trees around the Old Well at the iconic UNC in Chapel Hill, North Carolina

Weather in September

September marks the beginning of fall in Chapel Hill. With a considerable drop in temperatures from August, residents start experiencing cooler days and brisker nights. An evident change in the atmosphere becomes pronounced by a distinct fall crispness pervading the air. The decline in daylight hours further adds to the autumnal feel. Despite occasional rain showers, September's weather is largely pleasant, making it a perfect time to enjoy the city's stunning fall foliage against a backdrop of clear, blue skies.

Temperature

The beginning of September in Chapel Hill subtly marks a decrease in the average high-temperature, transitioning from a tropical 88°F (31.1°C) in August to a warm 82°F (27.8°C). During the nights in September, the temperature in Chapel Hill averages to an enjoyable 63.3°F (17.4°C).

Heat index

In September, the heat index is computed to be a hot 87.8°F (31°C). Uninterrupted activity during exposure could lead to a sense of exhaustion, possibly causing heat cramps.
From a standpoint of the heat index, values pertain to shaded conditions and mild breezes. The direct sunshine could escalate the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. The individual's impression of temperature can be affected by numerous factors such as metabolic variations, physical exertion, and attire. Direct exposure to the sun's rays can enhance the felt temperature, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.

Humidity

In September, the average relative humidity in Chapel Hill is 75%.

Rainfall

In September, the rain falls for 11.4 days. Throughout September, 0.98" (25mm) of precipitation is accumulated. In Chapel Hill, during the entire year, the rain falls for 130 days and collects up to 14.21" (361mm) of precipitation.

Snowfall

In Chapel Hill, snow does not fall in April through October.

Daylight

In September, the average length of the day in Chapel Hill is 12h and 23min.
On the first day of the month, sunrise is at 6:48 am and sunset at 7:43 pm. On the last day of September, in Chapel Hill, sunrise is at 7:11 am and sunset at 7:00 pm EDT.

Sunshine

In Chapel Hill, the average sunshine in September is 8.9h.

UV index

The average daily maximum UV index in September in Chapel Hill is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.
Note: A maximum UV index of 5 in September translates into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.

Frequently asked questions

What is the average September temperature in Chapel Hill?

In September, the average high-temperature and low-temperature in Chapel Hill, North Carolina, are 82°F (27.8°C) and 63.3°F (17.4°C) respectively. The average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines air temperature and relative humidity, in September is computed to be 87.8°F (31°C).

What is the average humidity in September in Chapel Hill?

In September, the average relative humidity is 75%.

How much does it rain in Chapel Hill in September?

In Chapel Hill, North Carolina, in September, during 11.4 rainfall days, 0.98" (25mm) of precipitation is typically accumulated.

When it does not snow in Chapel Hill?

April through October are months without snowfall in Chapel Hill.

What is the average length of the day in September in Chapel Hill?

In September, the average day length in Chapel Hill is 12h and 23min.

When is the sunrise / sunset in September in Chapel Hill?

On the first day of September in Chapel Hill, sunrise is at 6:48 am and sunset at 7:43 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 7:00 pm EDT.

How many hours of sunshine does Chapel Hill have in September?

The average sunshine duration in September in Chapel Hill, North Carolina, is 8.9h.

What is the UV index reading in September in Chapel Hill?

The average daily maximum UV index in September in Chapel Hill is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from exposure to the Sun's UV radiation.
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
Chapel Hill, NC

Average temperature in September - Chapel Hill, NC
  • Average high temperature in September: 82°F

The warmest month (with the highest average high temperature) is July (90.3°F).
The month with the lowest average high temperature is January (47.7°F).

  • Average low temperature in September: 63.3°F

The month with the highest average low temperature is July (69.4°F).
The coldest month (with the lowest average low temperature) is January (32°F).

Average pressure in September
Chapel Hill, NC

Average pressure in September - Chapel Hill, NC
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is November (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.96"Hg).

Average wind speed in September
Chapel Hill, NC

Average wind speed in September - Chapel Hill, NC
  • Average wind speed in September: 5.3mph

The windiest month (with the highest average wind speed) is April (7.3mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

Average humidity in September
Chapel Hill, NC

Average humidity in September - Chapel Hill, NC
  • Average humidity in September: 75%

The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is July (71%).

Average rainfall in September
Chapel Hill, NC

Average rainfall in September - Chapel Hill, NC
  • Average rainfall in September: 0.98"

The wettest month (with the highest rainfall) is May (1.77").
The driest month (with the least rainfall) is October (0.83").

Average rainfall days in September
Chapel Hill, NC

Average rainfall days in September - Chapel Hill, NC
  • Average rainfall days in September: 11.4 days

The month with the highest number of rainy days is July (15.1 days).
The month with the least rainy days is November (6.4 days).

Average snowfall in September
Chapel Hill, NC

Average snowfall in September - Chapel Hill, NC
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.47").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Chapel Hill, NC

Average snowfall days in September - Chapel Hill, NC
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is 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
Chapel Hill, NC

Average daylight in September / Average sunshine in September - Chapel Hill, NC
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 48min).

  • Average sunshine in September: 8h and 5min

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 24min).

Average sunshine days in September
Chapel Hill, NC

Average sunshine days in September - Chapel Hill, NC
  • Average sunshine days in September: 17.3 days

The month with the most sunshine days is October (22.3 days).
The months with the least sunshine days are July and August (12.8 days).

Average UV index in September
Chapel Hill, NC

Average UV index in September - Chapel Hill, NC
  • Average UV index in September: 5

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January and December (UV index 2).

Average cloud cover in September
Chapel Hill, NC

Average cloud cover in September - Chapel Hill, NC
  • Average cloud cover in September: 37

The months with the most cloud cover are February and March (Cloud cover 43).
The month with the least cloud cover is June (Cloud cover 31).

Average visibility in September
Chapel Hill, NC

Average visibility in September - Chapel Hill, NC
  • 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).

Chapel Hill, North Carolina, USA

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