March is the last month of the winter pattern. The lows are further apart than in January and the gaps between them longer, so a week here can hold a solid swell and two days of nothing.
The water runs late. Air temperature turns in March and the sea takes another six weeks to follow, so the beach can be pleasant at midday while the ocean is still at 13°C. Anybody who packs for spring gets cold.
Five months of storms have finished with the sand by now, and March is when the banks are at their least predictable of the year. Two beaches a kilometre apart can be a good wave and a shorebreak on the same tide, and no forecast tells you which is which.

