Overview
Charleston's climate is temperate, modified considerably by the proximity to the ocean. Summers are hot and humid, while winters are generally mild. The spring and fall are absolutely gorgeous. Temperature extremes are quite rare.
High temperatures are
generally several degrees lower along the coast than inland due to the
cooling effect of the sea breeze. The rain, except during occasional
tropical storms, generally occurs as showers or thunderstorms. Dry,
continental air masses reach this area in summer mostly by sliding down
the Atlantic coast and bringing cooler northeast winds. Such masses
reaching this area from the northwest or west in summer bring mostly
clear skies and high temperatures.
The winter months, December through February, are mild with periods of rain. However, the winter rainfall is generally of a more uniform type. There are infrequent snow flurries, with the best probability of occurrence in January, but significant amounts are rarely measured. An average winter would experience less than one cold wave and severe freeze. The average occurrence of the first freeze is in early December, and the average last freeze is late February, giving an average growing season of about 294 days.
The Ocean
The ocean off the S.C. coast
is quite hospitable to swimmers during the
Summer and early Fall. The water temperature climatology
shows waters
normally warm above 70° F in early May, cooling below 70° in
mid-October.
For surfers and
body-boarders, the biggest waves usually occur during the Spring and
Fall due to stronger winds. Long-period swell occasionally develop
during the Summer as a result of tropical cyclones well offshore.
The greatest hazard to anyone entering the surf are Rip Currents. If you're not familiar with them, now is a good time to brush up. They are responsible for about 100 deaths in the U.S. each year, but are not to be mistaken with the long-shore current. Read more about them here. Another significant hazard is lightning. Several people have been injured or killed in the last few years while walking or recreating on the local beaches. Many people don't realize lightning can strike you when it isn't raining. In fact, most lightning casualties are caused by "bolts from the blue", lightning bolts that originate from the side of a storm. Brush up on lightning safety tips here.
The Tropics
Hurricane season officially runs from June 1st until November 30th, but as 2005 proved, tropical cyclones can occur any time of year. The western Atlantic becomes much more active during August, September, and October, which is when the S.C. coast is most likely to be directly affected. Historically, S.C. is quite unlikely to have a direct strike from a hurricane. As the image shows, South Carolina has one of the highest return periods for hurricanes. Most tropical cyclones either cross Florida or recurve before striking the S.C. coast. The last major hurricane to make landfall on the S.C. coast was Hurricane Hugo, a Category 4 in 1989.
Despite the relatively low chances of encountering a tropical cyclone during your time in Charleston, it is imperative to be prepared. Due to the high population density and few transportation arteries in and out of the Lowcountry, evacuations are usually messy. It normally takes between 24 and 48 hours to effectively evacuate the coastal sections of Charleston. Therefore, getting out of the area before an evacuation is called is recommended. Learn the basics about tropical cyclones before the season starts.
Charleston's climate is temperate, modified considerably by the proximity to the ocean. Summers are hot and humid, while winters are generally mild. The spring and fall are absolutely gorgeous. Temperature extremes are quite rare.
High temperatures are
generally several degrees lower along the coast than inland due to the
cooling effect of the sea breeze. The rain, except during occasional
tropical storms, generally occurs as showers or thunderstorms. Dry,
continental air masses reach this area in summer mostly by sliding down
the Atlantic coast and bringing cooler northeast winds. Such masses
reaching this area from the northwest or west in summer bring mostly
clear skies and high temperatures. The winter months, December through February, are mild with periods of rain. However, the winter rainfall is generally of a more uniform type. There are infrequent snow flurries, with the best probability of occurrence in January, but significant amounts are rarely measured. An average winter would experience less than one cold wave and severe freeze. The average occurrence of the first freeze is in early December, and the average last freeze is late February, giving an average growing season of about 294 days.
The Ocean
The ocean off the S.C. coast
is quite hospitable to swimmers during the
Summer and early Fall. The water temperature climatology
shows waters
normally warm above 70° F in early May, cooling below 70° in
mid-October.
For surfers and
body-boarders, the biggest waves usually occur during the Spring and
Fall due to stronger winds. Long-period swell occasionally develop
during the Summer as a result of tropical cyclones well offshore. The greatest hazard to anyone entering the surf are Rip Currents. If you're not familiar with them, now is a good time to brush up. They are responsible for about 100 deaths in the U.S. each year, but are not to be mistaken with the long-shore current. Read more about them here. Another significant hazard is lightning. Several people have been injured or killed in the last few years while walking or recreating on the local beaches. Many people don't realize lightning can strike you when it isn't raining. In fact, most lightning casualties are caused by "bolts from the blue", lightning bolts that originate from the side of a storm. Brush up on lightning safety tips here.
The Tropics
Hurricane season officially runs from June 1st until November 30th, but as 2005 proved, tropical cyclones can occur any time of year. The western Atlantic becomes much more active during August, September, and October, which is when the S.C. coast is most likely to be directly affected. Historically, S.C. is quite unlikely to have a direct strike from a hurricane. As the image shows, South Carolina has one of the highest return periods for hurricanes. Most tropical cyclones either cross Florida or recurve before striking the S.C. coast. The last major hurricane to make landfall on the S.C. coast was Hurricane Hugo, a Category 4 in 1989.
Despite the relatively low chances of encountering a tropical cyclone during your time in Charleston, it is imperative to be prepared. Due to the high population density and few transportation arteries in and out of the Lowcountry, evacuations are usually messy. It normally takes between 24 and 48 hours to effectively evacuate the coastal sections of Charleston. Therefore, getting out of the area before an evacuation is called is recommended. Learn the basics about tropical cyclones before the season starts.