September Weather in Chapel Hill, United States

Last updated: February 24, 2025

September in Chapel Hill, United States, presents a vibrant blend of warm and mild weather. With maximum temperatures reaching 35°C (96°F) and an average of 23°C (74°F), the month is characterized by its warm days and cooler nights, dipping to a minimum of 9°C (48°F). Residents can expect nine days of precipitation, totaling 128 mm (5.1 in), adding a refreshing touch to the warm atmosphere. The air is often humid, averaging around 79%, creating a lush backdrop that highlights the region's natural beauty. Overall, September in Chapel Hill is a dynamic month that balances warmth with the refreshing onset of autumn.

September Temperature in Chapel Hill

In Chapel Hill, United States, September marks a delightful transition into autumn, characterized by milder temperatures. With a minimum of 9°C (48°F) and a maximum reaching 35°C (96°F), the month showcases comfortable averages around 23°C (74°F), making it one of the more pleasant times of the year. This dip in temperature from the sweltering summer months is a welcome change, as the city enjoys clear skies and gentle breezes. As the foliage begins to change and outdoor activities beckon, September invites both locals and visitors to revel in its varied climate before the cooler days of fall settle in. The trends of rising daytime averages paired with cooler evenings create a perfect backdrop for enjoying Chapel Hill’s vibrant community life.

September Weather in Chapel Hill: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Chapel Hill, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec434852617076807874655146
Data source: Temperature data for Chapel Hill generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Chapel Hill

In September, Chapel Hill experiences a notable peak in precipitation, with 128 mm (5.1 in) of rain recorded over 9 days. This aligns with the trend observed in the preceding months, particularly August, which also saw a similar amount of rainfall. As summer transitions into fall, the frequency of rainy days begins to taper off, setting the stage for a drier October ahead. The consistent high precipitation levels during these late summer months hint at a lush green landscape, while the diminishing rainy days suggest that locals can soon expect sunnier skies to accompany the cooler fall weather.

September Precipitation Trends in Chapel Hill

The chart displays monthly precipitation patterns in Chapel Hill, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec89117841161181211141281289781107
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Chapel Hill

In September, Chapel Hill experiences a slight dip in humidity, averaging around 79%. This marks a gradual decline as the summer months wind down; humidity levels peak at 85% in January and taper off to a comfortable 80% by October. Interestingly, this trend reveals a subtle transition as residents swap the sweltering heat of summer for the refreshing breezes of early fall. As the year progresses, humidity levels remain relatively stable, with only minor fluctuations, suggesting that September offers a brief respite before the higher humidity returns later in the year. Overall, this gentle decline reflects the shifting seasons, bringing a welcomed change in the air.

September Average Humidity in Chapel Hill

This chart illustrates the average monthly humidity levels in Chapel Hill, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec85%82%81%80%81%81%81%80%79%80%86%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chapel Hill

September in Chapel Hill, United States, ushers in a very high UV Index of 9, signaling that sun protection is essential. As summer gives way to fall, the UV levels slightly decrease from the extreme heights of July and August, where the index peaked at 11. Despite this reduction, the burn time remains a brisk 15 minutes, underscoring the need for vigilance against skin damage. With the sun's intensity gradually changing, residents and visitors alike should stay informed and adapt their sun safety measures accordingly. For more insights and trends, explore the Chapel Hill UV Index.

Maximum UV Index Levels in Chapel Hill for September

The chart shows the monthly maximum UV Index (UVI) for Chapel Hill in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109853
Data source: Chapel Hill September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Chapel Hill

As the warm days of September arrive in Chapel Hill, the sunshine continues to grace the region with an impressive 289 hours of radiant light, offering a delightful continuation of summer's glow. This month marks a slight dip from the peak of July's splendid 352 hours, yet it still maintains a vibrant luminosity compared to the early year. Following the lush abundance of May and June, which boasted 306 and 323 hours respectively, September showcases a pleasant transition into the fall season, allowing residents and visitors alike to relish in the golden hues of changing leaves under a sun-soaked sky. This trend highlights Chapel Hill’s warm climate, offering a unique charm that lingers long into autumn.

Monthly Sunshine Duration in Chapel Hill: September Highlighted

The September sunshine duration represents the total number of hours Chapel Hill experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec165h183h256h284h306h323h352h321h289h270h234h203h
Data source: Chapel Hill September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Chapel Hill During September

As September rolls into Chapel Hill, the likelihood of sunny weather begins to shine brighter, with a 58% chance of sunshine. This marks a notable increase from the summer months, where June and July see only 34% and 45% chances, respectively. In fact, after a relatively sunny April at 60%, September emerges as a strong contender for pleasant days. As the month unfolds, residents and visitors can expect a more favorable atmosphere before the leaves change and autumn takes hold, making it one of the better months for enjoying the outdoors.

Percentage of Sunny Days in September in Chapel Hill

The chart illustrates the percentage of sunny days in Chapel Hill throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Chapel Hill experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec48%36%43%60%39%34%45%52%58%48%63%45%
Data source: Chapel Hill September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Chapel Hill in September

As September unfolds in Chapel Hill, the daylight begins to wane, offering about 12 hours of sunlight each day. This transitional month marks a shift from the peak summer brightness of 14 hours in June, July, and August, gradually ushering in the shorter days of fall. The gradual decrease in daylight hours reflects nature's steady march towards winter, as mornings linger in darkness and evenings greet the stars just a bit earlier. This rhythm of light not only influences daily activities and moods but also heralds the vibrant seasonal changes that autumn brings, making September a month of both reflection and anticipation.

Average Daylight Hours in Chapel Hill for September

The chart illustrates the variation in daylight duration in Chapel Hill throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h10h 52m11h 59m13h 7m14h 5m14h 33m14h 18m13h 27m12h 21m11h 13m10h 14m9h 44m
Data source: Chapel Hill daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Chapel Hill

In September, Chapel Hill experiences a gentle shift in wind patterns, with an average speed of 2.4 m/s (5 mph), marking a subtle decline compared to the summer months. This cooling breeze signals the transition to autumn, creating a refreshing contrast to the hotter days of July and August, which recorded higher speeds. As the air begins to crisp, the wind lingers slightly beneath its summer peaks but paves the way for gusts that rise again in October and November. This trend illustrates a rhythm of seasonal change, where September serves as a calm interlude before the invigorating winds of fall take center stage.

Average September Wind Speed in Chapel Hill

The chart displays monthly wind speed patterns in Chapel Hill, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.73.23.23.32.62.42.52.02.4 m/s2.83.02.9
Data source: Chapel Hill September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Chapel Hill Compares to Other Months

The weather in Chapel Hill changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Chapel Hill and find detailed weather information for every month.

September and January showcase a stark contrast in weather patterns. In September, temperatures typically range from a mild minimum of 9°C (48°F) to a warm maximum of 35°C (96°F), with an average of 23°C (74°F). The month also sees considerable rainfall, accumulating 128 mm (5.1 in) over about 9 days, and a humidity level of 79%. In contrast, January experiences much colder temperatures, with a minimum of -15°C (6°F) and an average of just 6°C (43°F), peaking at 25°C (77°F) on warmer days. Although January has less precipitation at 89 mm (3.5 in) over the same number of rainy days, the humidity rises slightly to 85%. This clear seasonal shift highlights the significant differences in climate between these two months. For more details on January weather, check out Chapel Hill weather in January.

September and February showcase striking contrasts in weather. September boasts warmer temperatures, with averages around 23°C (74°F) and highs reaching up to 35°C (96°F), while February's average settles at a much cooler 9°C (48°F), with maximums of 27°C (81°F). Additionally, September typically experiences more precipitation, totaling 128 mm (5.1 in) over 9 days, compared to February's 117 mm (4.6 in) over 11 days. Humidity levels are relatively similar, with September at 79% and February slightly higher at 82%. For more details, check out Chapel Hill weather in February.

In comparing the weather between September and March, we see significant contrasts in temperature and precipitation. September typically enjoys warmer conditions, with average temperatures ranging from a minimum of 9°C (48°F) to a maximum of 35°C (96°F), culminating in an average of 23°C (74°F). However, it also experiences higher precipitation levels of 128 mm (5.1 in) over about 9 days, coupled with a humidity level of 79%.

In contrast, March tends to be cooler, with temperatures ranging from a minimum of -5°C (24°F) to a maximum of 31°C (88°F), leading to an average temperature of 11°C (53°F). Additionally, March sees less rainfall, with 84 mm (3.3 in) over 10 days and slightly higher humidity at 81%. For more detailed insights, you can check the Chapel Hill weather in March.

In September, temperatures tend to be warmer with a minimum of 9°C (48°F) and a maximum reaching up to 35°C (96°F), while the average temperature hovers around a comfortable 23°C (74°F). The month experiences about 128 mm (5.1 in) of precipitation over 9 days, with humidity levels sitting at 79%. In contrast, April presents cooler weather, with temperatures ranging from a brisk minimum of -1°C (31°F) to a maximum of 31°C (88°F) and an average of 16°C (62°F). The precipitation in April is slightly less at 116 mm (4.6 in) across 10 days, accompanied by a similar humidity level of 80%. For more details about the weather in this spring month, visit Chapel Hill weather in April.

In comparing the weather of September and May, September typically experiences warmer conditions, with average temperatures around 23°C (74°F) and maximums reaching up to 35°C (96°F). In contrast, May has a slightly cooler average temperature of 21°C (70°F), yet it can still peak at a maximum of 36°C (97°F). Both months see similar levels of precipitation, with September averaging 128 mm (5.1 in) over 9 days and May recording 118 mm (4.6 in) across 11 days. The humidity levels are fairly consistent, with September at 79% and May slightly higher at 81%. For more detailed weather information, you can visit Chapel Hill weather in May.

When comparing the weather in September to that of June, several notable differences emerge. September generally experiences a wider temperature range, with minimums dipping to 9°C (48°F) and maximums reaching up to 35°C (96°F). In contrast, June has milder minimums at 12°C (55°F) and slightly higher maximum temperatures of 36°C (97°F). Precipitation levels are similar, with September averaging 128 mm (5.1 in) over 9 days, while June sees 121 mm (4.8 in) over a slightly longer duration of 13 days. Humidity remains fairly consistent between the two months, with September at 79% and June slightly higher at 81%. For more detailed insights, you can check out Chapel Hill weather in June.

In comparing the weather of September and July, notable differences emerge. September experiences a wider range of temperatures, with a minimum of 9°C (48°F) and a maximum of 35°C (96°F), leading to an average temperature of 23°C (74°F). This month also sees higher precipitation levels of 128 mm (5.1 in) over 9 days, resulting in a humidity level of 79%. In contrast, July is generally warmer, with minimum temperatures of 16°C (61°F) and maximums reaching 37°C (99°F), and an average of 27°C (80°F). It has slightly lower precipitation at 114 mm (4.5 in) but experiences more rainy days, totaling 14, and marginally higher humidity at 81%. For a detailed overview of July's weather conditions, you can visit Chapel Hill weather in July.

September weather features a notable drop in minimum temperatures, with lows around 9°C (48°F) compared to the warmer 15°C (59°F) in August. The average temperature in September is slightly lower at 23°C (74°F) versus August's 26°C (78°F). While both months experience similar total precipitation of 128 mm (5.1 in), September sees a reduction in rainy days, with rain occurring on 9 days compared to 15 in August. Additionally, humidity levels remain high, with September at 79% and August at 80%, making both months feel quite humid. For more details, you can check Chapel Hill weather in August.

In comparing the weather of September and October, September boasts significantly warmer temperatures, with an average high of 35°C (96°F) and lows around 9°C (48°F). In contrast, October experiences cooler conditions, featuring an average high of 36°C (98°F) but a lower average temperature of 18°C (65°F), along with a chilly minimum of 2°C (36°F). Precipitation also decreases from September's 128 mm (5.1 in) to October's 97 mm (3.8 in), although both months see rainfall on about 9 days. Humidity levels remain relatively similar, hovering around 79% in September and slightly increasing to 80% in October. For more detailed weather insights, visit Chapel Hill weather in October.

September and November present distinct weather patterns. In September, temperatures range from a comfortable 9°C (48°F) to a scorching 35°C (96°F), with an average of 23°C (74°F). The month sees considerable rainfall, totaling 128 mm (5.1 in) over 9 days, and humidity levels average around 79%. In stark contrast, November experiences much cooler temperatures, dipping to a minimum of -4°C (25°F) and peaking at 29°C (84°F), with a notable average of 10°C (51°F). Rainfall is less frequent, accumulating to 81 mm (3.2 in) over just 7 days, and humidity rises slightly to 85%. For more details about the weather in November, you can check out Chapel Hill weather in November.

September and December present contrasting weather conditions. In September, temperatures range from a minimum of 9°C (48°F) to a maximum of 35°C (96°F), with an average of 23°C (74°F), creating a warm and often humid atmosphere with 79% humidity. The month sees significant precipitation, totaling 128 mm (5.1 in) over 9 days. In stark contrast, December experiences much colder temperatures, with a minimum of -7°C (19°F) and a maximum of 23°C (73°F), averaging just 8°C (46°F). Although December has slightly less precipitation at 107 mm (4.2 in), the humidity rises to 86%, contributing to a crisp, chillier environment. For more details, check out Chapel Hill weather in December.

Compare Chapel Hill's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Chapel Hill

As summer fades and autumn approaches, September in Chapel Hill presents a refreshing shift in weather. With average temperatures comfortably hovering around 23°C (74°F), the month offers a welcome reprieve from the summer heat, though occasional peaks can reach up to 35°C (96°F). The days become subtly shorter, and the 79% humidity adds a touch of warmth to the cooler evenings, often dipping to a minimum of 9°C (48°F). Although rainfall makes its presence felt with 128 mm (5.1 in) across 9 days, these showers nourish the local landscapes and contribute to the season’s vibrant transformation. Overall, September’s blend of warm days and cooler nights creates a perfect backdrop for enjoying the evolving beauty of Chapel Hill. For a deeper understanding of seasonal variations, visit Chapel Hill Climate.