In contrast to their northern cousin, South Carolina and Georgia have a wide continental shelf which drains power from the incoming waves. Autumn brings the hurricane season to South Carolina and the best surf with the oncoming winter providing reasonably consistent, but only occasionally good, conditions. Offshore winds are generally from the west, but the varied topography means almost limitless options. Georgia suffers the same benefits and issues with the possibility of excellent surf on the relatively unexplored outlying barrier islands. The summers are extremely flat but the occasional swells are often accompanied by favourable winds. Temperatures are mild in winter but the sea can drop to 9°C/48°F rising to 25°C/77°F in summer. Man made structures such as groynes provide the banks for surfing along much of this coast, which was first surfed in the 1930s and popularised by servicemen in 1963.