Last updated: February 24, 2025
In September, Charleston experiences a delightful transition, characterized by an average temperature of 26°C (78°F). The month showcases maximum highs reaching up to 35°C (94°F), while evenings bring a refreshing minimum of 14°C (57°F). September is also marked by a significant rainfall with 176 mm (6.9 in) spread over 14 days, contributing to a notable humidity level of 83%. This blend of warmth and moisture creates a vibrant atmosphere, perfect for enjoying the city's rich history and stunning coastal scenery.
As September unfolds in Charleston, temperatures begin to shift subtly, reflecting a transition from the sweltering summer heat. The month starts with a pleasant minimum temperature of 14°C (57°F), gradually warming to an average of 26°C (78°F) during the day. Highs can reach up to 35°C (94°F), keeping summer's warmth lingering just a bit longer. Notably, the drop in minimum temperatures signals a forthcoming change, hinting at the crispness of fall. This trend showcases Charleston's characteristic blend of lingering warmth with an inviting hint of cooler days ahead, perfect for enjoying the outdoors.
In September, Charleston experiences a significant transition in its weather patterns, with a notable precipitation total of 176 mm (6.9 in) over 14 days of rain. This marks a slight decline from the peak summer months, where both July and August saw higher rainfall totals of 187 mm and 183 mm, respectively. However, the lingering humidity of late summer continues to influence the weather, leading to frequent rain showers. The rainfall during September, while still substantial, hints at the approaching shift into fall, where average precipitation begins to drop. This gradual decrease sets the stage for a crisp, more temperate climate in the months ahead, providing a refreshing reprieve after the heavy summer downpours.
As summer transitions into fall, September in Charleston brings an average humidity of 83%, a slight uptick from the previous months of July and August, which hovered around 80% and 81%, respectively. This subtle increase reflects the lingering warmth of the season, as the city starts to prepare for the cooler days ahead. The humidity generally declines after September, with October readings dropping to 78%, yet it still remains higher than the annual average. Notably, the patterns show a peak during the winter months, with December reaching a high of 87%, while the summer months maintain relatively consistent humidity levels. This trend highlights Charleston's characteristic moist environment, setting the stage for its vibrant fall atmosphere.
In September, Charleston experiences a notable shift in the UV Index, which measures 9—indicating a very high risk of harm from unprotected sun exposure. This drop from the extreme levels seen throughout the summer months is a welcome change, yet residents and visitors should still be vigilant, with a burn time of just 15 minutes for fair-skinned individuals. As autumn approaches, the trend reveals a gradual reduction in UV exposure, transitioning from the scorching heat of July and August towards a cooler October, which still maintains a very high index of 8. This pattern underscores the importance of sun safety practices year-round. For more detailed information on UV levels throughout the year, visit Charleston UV Index.
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As summer gracefully transitions into fall, September in Charleston enjoys a delightful 300 hours of sunshine, maintaining the warmth of the season while hinting at cooler days ahead. After the peak of 341 hours in July, sunshine hours gradually taper off, with September still boasting a substantial amount of daylight. This month sets the stage for the shifting patterns of autumn, where the vibrant hues of nature begin to emerge. Following the earlier months of 336 hours in May and 316 hours in June, September offers a perfect balance of sun-soaked days, making it an ideal time for outdoor exploration and enjoying the coastal charm before the cooler October days set in. The trend shows a graceful decline from the summer's exuberance, yet September holds its own, inviting residents and visitors alike to bask in the lingering warmth.
As summer transitions into autumn in Charleston, the likelihood of sunny weather in September showcases a promising 51%. This gradual shift reflects a significant improvement from the peak months of summer, where the chances of sunny days consistently dip to the low thirties. Interestingly, September's forecast is notably higher than both June and July, hinting at a more favorable climate as the intense heat wanes. Moreover, as we approach October, the probabilities remain close at 50%, suggesting that the region may continue to enjoy pleasant, sunlit days, especially as it drifts towards fall. This trend underscores September’s appeal as a delightful month for outdoor activities in the Lowcountry.
As September arrives in Charleston, the days begin to subtly shorten, offering about 12 hours of daylight—a gentle transition from the lengthy, sun-soaked days of summer. This month marks a slight decrease from the peak daylight hours of 14 in June and July, while maintaining the comfortable warmth that characterizes early fall. Interestingly, this gradual waning of daylight hints at the impending autumn, as October's hours further dip to 11. Overall, September serves as a beautiful bridge between the vibrant summer and the cooler, more subdued months ahead, allowing residents and visitors to savor the lingering light before the shorter days of winter set in.
As September rolls into Charleston, the gentle breezes of early fall begin to replace the sweltering summer air. The average wind speed in September stands at 2.9 m/s (6 mph), slightly more vibrant than August's lull, yet still among the calmest months of the year. This transition marks a shift from the peak summer winds, which dipped to a low of 2.8 m/s in August, signaling that the height of summer's humidity is slowly giving way to a more refreshing atmosphere. As we look ahead, wind speeds begin to creep up again in October, hinting at the Caribbean influences and cooler fronts that dance along the coast. This delicate balance sets the tone for September—a month where the mild winds invite leisurely strolls along the historic streets and a chance to relish the lingering warmth of the season.
The weather in Charleston 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 Charleston and find detailed weather information for every month.
September weather is characterized by warm temperatures, with averages around 26°C (78°F) and highs reaching up to 35°C (94°F). However, it is also marked by significant humidity at 83% and frequent rainfall, totaling 176 mm (6.9 in) over about 14 days. In contrast, January experiences much colder conditions, with average temperatures dropping to 11°C (52°F) and minimums plunging as low as -13°C (9°F). The precipitation is notably less, with only 59 mm (2.3 in) falling across 7 days, while humidity levels remain high at 86%. For more detailed information, check out Charleston weather in January.
In September, the weather is notably warmer, with average temperatures ranging from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), bringing a humid feel with 83% humidity. This month also experiences significant rainfall, averaging 176 mm (6.9 in) spread across about 14 days. In contrast, February presents a much cooler climate, with temperatures ranging from a low of -2°C (29°F) to an average high of 26°C (79°F). The precipitation in February is considerably lower, at 78 mm (3.1 in) over approximately 9 days, coupled with slightly lower humidity at 81%. For more detailed information on February weather, you can visit Charleston weather in February.
September and March present a striking contrast in weather conditions. In September, temperatures soar with a minimum of 14°C (57°F), averaging a warm 26°C (78°F), and peaking at a sweltering 35°C (94°F). This month also sees considerable rainfall, with 176 mm (6.9 in) spread over 14 days, resulting in high humidity levels averaging 83%. In contrast, March ushers in cooler temperatures, with a minimum of -1°C (30°F), an average of 15°C (60°F), and a maximum of 28°C (82°F). The precipitation is significantly lower, totaling 60 mm (2.4 in) across just 6 days, and humidity is slightly reduced at 81%. For more detailed information about weather conditions during this month, visit Charleston weather in March.
When comparing the weather in September and April, we see distinct differences in temperature and precipitation patterns. September offers warmer temperatures, with averages around 26°C (78°F) and maximums reaching up to 35°C (94°F). The month also experiences higher humidity at 83% and significant precipitation, totaling 176 mm (6.9 inches) over 14 days. In contrast, April has cooler temperatures, with an average of 19°C (66°F) and maximums of 31°C (89°F). Additionally, April has less precipitation, totaling 101 mm (4.0 inches) over just 8 days, and slightly lower humidity at 79%. For more detailed information on April's weather, you can visit Charleston weather in April.
September and May present distinct weather patterns, reflecting the transition between seasons. September enjoys warmer average temperatures, ranging from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), while May has slightly cooler averages, with minimums around 9°C (49°F) and maximums reaching 37°C (98°F). Rainfall is more pronounced in September, averaging 176 mm (6.9 in) over 14 days, making it a more humid month at 83% humidity compared to May’s drier conditions with just 87 mm (3.4 in) over 9 days and 75% humidity. This variation creates a more conducive outdoor environment in May, making it an ideal time for activities in Charleston. For more details, check Charleston weather in May.
In comparing the weather of September and June, both months exhibit relatively warm temperatures, with June having a slightly higher minimum temperature of 16°C (61°F) compared to September's 14°C (57°F). The average temperature remains consistent at around 26°C (79°F) for both months, but September experiences higher overall humidity at 83%, compared to June's 75%. Rainfall is another notable difference, as September sees more precipitation at 176 mm (6.9 inches) over 14 days, while June has 150 mm (5.9 inches) over 19 days. For a deeper dive into the specifics of June weather in Charleston, you can check Charleston weather in June.
When comparing the weather in September to July, September experiences slightly cooler temperatures, with a minimum of 14°C (57°F) and an average of 26°C (78°F), while July features warmer nights, with a minimum of 20°C (69°F) and an average of 28°C (82°F). Both months see high temperatures reaching up to 34°C (94°F), but September tends to be more humid, averaging 83% compared to July's 80%. In terms of precipitation, September has a total of 176 mm (6.9 in) over 14 days, which is slightly less than July's 187 mm (7.4 in) spread across 20 days. For more details on July's specific weather patterns, you can visit Charleston weather in July.
In comparing the weather of September and August, September tends to be slightly cooler, with average temperatures ranging from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), whereas August has warmer nights, with a minimum temperature of 21°C (70°F) and a similar maximum at 35°C (95°F). Precipitation in September totals 176 mm (6.9 in) over 14 days, marking a slight decrease compared to August's 183 mm (7.2 in) over 21 days. Despite September experiencing more rainfall, it also has higher humidity at 83%, compared to August's 81%. For a more detailed look at August weather, you can visit Charleston weather in August.
September and October exhibit a notable transition in weather patterns. In September, temperatures range from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), with an average of 26°C (78°F). This month experiences considerable rainfall, totaling 176 mm (6.9 in) over 14 days, coupled with high humidity levels at 83%. In contrast, October brings cooler temperatures, with a minimum of 3°C (38°F) and a maximum of 31°C (89°F), averaging 22°C (72°F). Precipitation decreases significantly to 79 mm (3.1 in) over just 9 days, and humidity slightly lowers to 78%. For more insights, check out Charleston weather in October.
September and November present contrasting weather patterns. In September, temperatures are notably warmer, with a minimum of 14°C (57°F), an average of 26°C (78°F), and a peak reaching 35°C (94°F). This month also experiences significant rainfall, with 176 mm (6.9 in) spread over 14 days, accompanied by high humidity at 83%. In contrast, November ushers in cooler temperatures, with a minimum dipping to -1°C (31°F), an average of 15°C (59°F), and a maximum of 28°C (84°F). Precipitation decreases to 92 mm (3.6 in) over 8 days, while humidity remains high at 85%. For more details on November weather, you can visit Charleston weather in November.
September and December present strikingly different weather patterns. In September, temperatures range from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), with an average of 26°C (78°F), making it a warm and humid month with 83% humidity. The month also sees significant rainfall, totaling 176 mm (6.9 in) over about 14 days. In contrast, December experiences much cooler temperatures, with a minimum of -3°C (28°F) and a maximum of 25°C (77°F), averaging around 12°C (54°F). Precipitation during this month is lower, at 127 mm (5.0 in) over 9 days, and the humidity rises slightly to 87%. For more details on December weather patterns, you can check Charleston weather in December.
As summer gives way to fall, September in Charleston showcases a unique blend of warmth and humidity that marks a transition from the sweltering heat of previous months. With an average temperature that remains comfortably warm, the days can still feel quite hot, but the nights bring a welcome coolness. While the city does experience notable rainfall, often seen in brief yet intense showers, the lush surroundings become even more vibrant. This month stands out with its high humidity, enveloping the area in a tropical embrace. For those looking to understand the seasonal shifts and climatic nuances, exploring further through Charleston Climate provides valuable insights.