Saint Croix, United States Virgin Islands offers 1 beach perfect for sunbathing, surfing, swimming, and more. Saint Croix is known for Buck Island Reef National Monument and Christiansted National Historic Site. The best time to travel to Saint Croix is from December to April, with average air temperatures around 77-82°F (25-28°C) and water temperatures about 79-82°F (26-28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!