Costa Verde in December

May through September offers the most reliable weather, but each month brings different advantages. June and July deliver long days and warmest water temperatures - though 'warm' is relative when you're talking about the Atlantic. August brings Portuguese families on holiday, so expect crowds at the main beaches. September might be the sweet spot: still warm enough for swimming, fewer crowds, and the light gets that golden quality photographers love. Winter storms are spectacular to watch from clifftop cafes, but most coastal restaurants close November through March. Spring wildflowers carpet the coastal paths in April and May, making it prime hiking season despite unpredictable weather.