Ballymulderry, Ireland offers 1 beach perfect for sunbathing, surfing, swimming, and more. Ballymulderry is known for the Ballymulderry Castle and the annual Ballymulderry Music Festival. The best time to travel to Ballymulderry, Ireland, is from May to September, with average air temperatures around 15-20°C (59-68°F) and water temperatures around 12-16°C (54-61°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!