September in Charleston starts out hot and humid, but temperatures gradually become more comfortable as the month progresses. The mornings and evenings tend to feel more pleasant toward the end of the month, although humidity remains common.
If you're planning a trip to Charleston in September, you'll still want to be prepared for summer-like weather, especially early in the month. Lightweight clothing, comfortable walking shoes, sunscreen, and an umbrella or lightweight rain jacket are all useful to have.
My experience as a retired meteorologist, combined with my work as a Charleston tour guide, allows me to provide reliable information about what you can expect from Charleston weather in September.
Charleston Weather in September at a Glance
Average daytime temperatures:
- Mid-80s F (around 27-30 C)
- Average nighttime temperatures: Upper 60s to mid-70s F (around 20-24 C)
- Rain: Measurable rain falls on about 8-9 days
- Thunderstorms: Around 5 days on average
- Ocean temperature: Around 79-82 F (26-28 C)
- Daylight: About 12 hours by the end of September
- Humidity: High, especially early in the month
- Hurricane risk: Tropical activity peaks during September
How Hot is Charleston in September?
September is still a warm month in Charleston, although temperatures gradually become more comfortable as the month progresses. Daytime high temperatures tend to average around 84-86 F (29-30 C) early in the month, cooling to around 80-81 F (27 C) toward the end of September.
On average, Charleston records high temperatures of 90 F (32 C) or higher on about 3-5 days during September, with most of these hot days occurring early in the month. The record high temperature for Charleston in September is 99 F (37.2 C).
If you're planning to spend the day walking around downtown Charleston, the heat and humidity can still make it feel warmer than the actual temperature, particularly early in the month. Consider scheduling longer walking activities for the morning or late afternoon, and take breaks in the shade or indoors during the warmest part of the day.
Nighttime temperatures remain warm but gradually become more comfortable. Late-night and early-morning lows tend to be around 73-75 F (23-24 C) at the beginning of September, cooling to approximately 68-70 F (20-21 C) by the end of the month.
A few cooler mornings, particularly later in the month, can dip to around 57 F (14 C). The record low temperature in Charleston during September is 42 F (5.6 C).
Does It Rain Often in September?
Rain is still common in Charleston during September, although rainfall doesn't necessarily mean you'll have a rainy vacation. Showers and thunderstorms can move through relatively quickly, leaving plenty of time to explore the city.
On average, Charleston has about 7 sunny days, 10 partly sunny days, and 13 mostly cloudy days during September.
Measurable rain falls on approximately 8-9 days during the month. However, only about 3 days typically record rainfall of 0.5 inches (12.7 mm) or more.
Thunderstorms occur on an average of about 5 days in September, with most of these occurring early in the month. Storms can bring heavy rain, lightning, and strong wind gusts, but they often don't last all day.
If you're visiting Charleston in September, it's a good idea to check the forecast each morning and be flexible with your plans. A morning walking tour can be a good choice on a day when thunderstorms are expected later in the afternoon.
How Much Daylight Does Charleston Get in September?
The days become noticeably shorter throughout September as summer transitions into fall.
Charleston receives about 12.8 hours of daylight on September 1 and approximately 11.9 hours of daylight by September 30.
You will still have plenty of daylight for sightseeing, especially early in the month. By the end of September, sunset comes noticeably earlier, so you may want to plan outdoor activities earlier in the day and enjoy Charleston's restaurants and nightlife in the evening.
How Windy Is Charleston in September?
Winds are generally light to gentle in September, typically ranging from about 4-12 mph (6-19 kph).
Stronger winds are possible during thunderstorms and tropical weather, particularly when a tropical system is approaching the coast. If you're spending time near the water or on the beach, conditions can also feel breezier than they do in downtown Charleston.
What Is the Ocean Temperature in Charleston in September?
September is still a great time for swimming and beach activities around Charleston. Ocean temperatures remain warm throughout the month, although the water gradually cools as fall approaches.
Ocean temperatures average around 82 F (28 C) early in September, cooling to about 79 F (26 C) by the end of the month.
If you're planning to visit the beach during your Charleston vacation, September's warm ocean temperatures are one of the advantages of traveling during this month. Just remember to use sunscreen and stay hydrated, especially during the warmer days early in the month.
Conditions can change with weather, tides, and surf, so check local conditions before heading into the water.
Is September Hurricane Season in Charleston?
Yes. September falls within the Atlantic hurricane season and is typically the peak month for tropical activity.
Historically, a named tropical storm or hurricane has passed within 175 miles of Charleston approximately once every two years. However, this does not mean that a storm will affect Charleston during any particular September.
If you're traveling to Charleston in September, it's wise to monitor the weather forecast, particularly if a tropical system is developing in the Atlantic. Travelers should also be aware of their hotel's cancellation policies and have a flexible plan if severe weather threatens the area.
The risk of a tropical storm or hurricane activity peaks in September, with a named tropical storm or hurricane passing within 175 miles of Charleston about every two years.
What to Wear in Charleston in September
The weather in Charleston in September can still feel like summer, especially early in the month, so lightweight, breathable clothing is your best choice.
Consider packing:
- Lightweight shirts and tops
- Shorts or lightweight pants
- Comfortable walking shoes
- Sandals
- A hat and sunglasses
- Sunscreen
- An umbrella
- A lightweight waterproof jacket or rain jacket
- A lightweight jacket and long pants for cooler mornings later in the month
- A change of clothes if you'll be walking outdoors for several hours
If you plan to visit nicer restaurants or go out in the evening, you may also want to pack a slightly dressier outfit and comfortable evening shoes.
Most importantly, bring comfortable walking shoes. Charleston is best explored on foot, and you'll likely spend more time walking outdoors than you expect.
Things to Do in Charleston in September
September can be a great month to explore Charleston. While the beginning of the month can still be hot and humid, temperatures gradually become more comfortable, making it easier to spend time outdoors.
Charleston Weather in September: Walking Tour Tips
There should still be plenty of warm days to explore Charleston's historic streets on foot. Our Charleston walking tours offer flexible pricing, so you can choose to pay what you wish or prepay your reservation in advance.
A morning walking tour can be a good choice early in the month when temperatures are warmer, while later September can offer more comfortable conditions throughout the day.
Watch a Charleston RiverDogs Game
The Charleston RiverDogs' season typically comes to an end in September, so you might want to catch one of their final home games of the year. Check the schedule and get tickets in advance, especially if a popular game or special event coincides with your visit.
Attend the Lowcountry Jazz Festival
The Lowcountry Jazz Festival is usually held in September and features live performances from jazz musicians. If you're looking for music or entertainment during your visit, check the festival website for the current schedule and event details.
Charleston Weather in September: Outdoor Activities
September's warm weather makes it a good time to explore Charleston's parks, waterfront, gardens, and historic neighborhoods.
If a hot or rainy afternoon interrupts your plans, take a break at a cafรฉ, restaurant, museum, or other indoor attraction before heading back outside.
Explore Charleston in the Evening
As the days become shorter and temperatures cool in the evening, September can be a pleasant time to explore Charleston after sunset.
Consider enjoying dinner outdoors, taking an evening stroll through the historic district, or joining a Charleston ghost tour to experience a different side of the city after dark.
More Things to Do in Charleston in September
Weather is only one part of planning your Charleston trip. September also brings seasonal events, live music, outdoor activities, and plenty of ways to explore the city's historic neighborhoods.
For more ideas and recommendations, check out our complete guide to things to do in Charleston in September and start planning your visit.
Fred Pickhardt
