Sao Silvestre, Portugal offers 1 beach perfect for sunbathing, surfing, swimming, and more. Coimbra is known for the University of Coimbra, a UNESCO World Heritage site. The best time to travel to Sao Silvestre, Portugal, is from June to September, with average air temperatures around 75°F (24°C) and water temperatures near 70°F (21°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!