Winter, December through February
The best driving weather of the year: daytime highs in the sixties and low seventies, low humidity, no insects to speak of. Camellias bloom in the coastal gardens. Occasional cold fronts drop temperatures into the forties overnight. This is also the season when northern visitors fill the beach towns, so book lodging ahead.
Spring, March through May
Azaleas in the gardens, comfortable temperatures, and the clearest light of the year for photography. Spring break traffic peaks on the coast in March but barely touches the inland route. By late May humidity is building and afternoon thunderstorms start.
Summer, June through September
Hot, humid, and reliably stormy in the afternoon. Start early, be off the trails by two, and use the middle of the day for museums. Mosquitoes and biting flies are serious in the swamp preserves. This is hurricane season, and coastal erosion from past storms has periodically closed segments of the beach road for repairs, so check road conditions before you commit to the coastal leg.
Fall, October and November
The quiet reward. Humidity breaks, crowds thin, water is still warm, and the light gets long. For a slow drive with the windows down, this is the best month range on the calendar.
Time of day
Morning belongs to the coast, when the sun is over the water and the pier is at its best. Late afternoon belongs to the interior, when low sun rakes across fields and the oak canopy on the old road glows. Midday is for the museums and the shaded ruins.