I was at Allonby on a hot afternoon. Look at the flags. They are blowing away from the sea. The wind always comes off the sea and onto the land on a hot day. The land has a lower specific heat capacity than the sea. It is also duller. It absorbs more infra-red heat radiation and the same heat energy gets it to reach a higher temperature sooner. Thus the air above the land reaches a higher temperature than the air above the sea. Air above the land expands, becomes less dense and floats up. It cools at height, shrinks, becomes more dense and sinks over the sea. At ground level it completes the loop by moving back in from the sea to the land. The on-shore breeze is part of a convection cycle.
