High season is pretty much any season in Charleston, aside from maybe the hottest stretch of the year, from mid-July through early September. That means reservations are always a good idea at restaurants, and a must for hotels downtown. Although you can call around a few days ahead for most tables, the top tier often require a week or more advanced booking for Friday or Saturday nights. And holidays (Thanksgiving, Christmas, New Year's Eve and Day, Valentine's Day, Mother's Day, or Easter brunch) demand reservations made a month or more prior. For those willing to fly by the seat of their schedules, same-day (and discounted) hotel reservations are available through the Lowcountry Reservation Service, operated at the Charleston Area Convention & Visitors Bureau, the Isle of Palms Visitor Center, and the North Charleston Visitors Center.