Hagatna, Guam offers 1 beach perfect for sunbathing, surfing, swimming, and more. Hagatna, Guam, is known for the Plaza de Espana and the Dulce Nombre de Maria Cathedral Basilica. The best time to travel to Hagatna, Guam, is from January to May, with average air temperatures around 81°F (27°C) and water temperatures near 82°F (28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!