Amboy, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Amboy, Washington, United States, is known for its proximity to Mount St. Helens National Volcanic Monument. The best time to travel to Amboy, United States, is in the spring (March to May) when the average air temperature is around 70°F (21°C) and water temperatures are not applicable as it is a desert area. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!