March is such an uncertain month. You could have mild weather one week and snow the next. And being at the beach, you’ll likely have wind, which always makes the temperature feel a bit cooler. You may want to have a contingency plan. The good thing is you probably won’t have to worry about hotel reservations - you should be able to find a vacancy at that time of year - so if you have a plan A and a plan B, then you can decide based on the weather.