Charleston is a wonderful city to explore on foot as the area is coastal and is blessed with nice weather for most of the year. Many visitors find that having a car is unnecessary as most of the historic sites, restaurants and shops are within walking distance.
The best weather for visiting depends on what you would like to do.
SPRING: Pick the springtime (Mid-March through the end of May) if you like to see Charleston's beautiful azaleas, magnolias, the famous Lady Banks rose, peach blossoms, dogwoods, etc.! The Historic Society runs daily home and garden tours from mid-March through mid-April. Expect springtime temperatures to average about 65-70 through March, 70-75 through mid-April, 75-80+ through May.
FALL: For fall foliage, make your visit from late September through mid-November, when the Preservation Society holds it's month long tours of homes and gardens. Many of these tours are offered in the evening, and the candlelght provided in the courtyards enhances the experience of visiting Charleston's uniquely beautiful gardens. Temperatures cool from 85 in September, dropping about 5 degrees every two weeks or so.
SUMMER: A very popular time to visit the beaches surrounding Charleston is from June 1 through Sept 30. It is then that the daytime temperatures make one yearn for the breezes that are always present offshore, providing beachgoers with comfort while taking long strolls on the firmly packed sand or while building sandcastles and memories. During the summer, weekly or monthly beachside rentals make for popular lodging on the nearby beaches of Folly Beach, Sullivan's Island, and Isle of Palms(10 to 20 minutes away) or the more distant resort islands of Kiawah and Seabrook. The types of rentals available range from hotel-like rooms to fully furnished 12-bedroom beachfront homes in golf course communities.
For about 6 weeks in the summer humidity and temperatures are extreme, (90 percent humidity with 90 degree temperatures) but even then coastal breezes can make exploring more comfortable. The water temperatures in late summer are bath-like - with August ocean temperatures around 85 degrees.
If you plan to visit the city when it is hot and humid you can combat the heat by walking on the shady side of the street, wearing a hat and sun lotion and drinking plenty of water and the southern favorite, "sweet tea". In Charleston, tree-lined streets and shade are not hard to find and are as common as well-airconditioned shops, restaurants and tourist sites. A boat ride on the harbor will always provide you with moving air that seems to lower the temperatures by 10 degrees or more. For temperatures you should expect for your visit, go to the weatherunderground site, where you can see weather data from previous years for any date you choose.
The only time of year not yet mentioned above is the span from mid-November to mid-March. This is generally the season in which you will find the best hotel deals, the smallest crowds, and the most variable weather. It is also the best time to view the city's lovely Camellias, which give Charleston so much color while the azaleas are "resting". The temperature can be 70 in the daytime one day and 30 the next day, but you should expect daytime highs to be around 55 and lows around 35. Charleston typically does not get snow and any cold snaps are generally short in duration. Many people can be found year-round on Charleston-area beaches throughout winter as beachwalking, dogwalking and bikeriding are still very popular ways for Charlestonians to get their exercise. WInter is also when area Oyster Festivals take place, which are common fundraisers for firehouses, churches, etc.
Of course there is always plenty to see and do any time of the year which makes this lovely and unique coastal city a must visit for anyone.