Most Chileans take their annual holiday in February, when all the resort towns are unbearably crowded. They also get busy on December and January weekends, but outside these times are remarkably quiet. November and March are probably the best months to visit, as the weather is usually agreeable and the beaches virtually deserted, especially midweek. Even in summer, however, the coast is prone to fog or cloudy weather, and temperatures in Valpo can be considerably lower than in Santiago.
From April to October accommodation rates in Viňa are sometimes half of those listed, and even in November, December and March you should be able to negotiate a midweek discount; rates in Valpo are pretty stable throughout the year, save at New Year when they double or triple. Some, but not all, beaches are safe for swimming, though you should definitely stay out of the water if a red flag is displayed; you might also be put off by the frigid Humboldt current, which leaves the water chilly even in the height of summer.