Dana Point's southern California climate makes it pleasant nearly year-round, but seasons differ in useful ways.
Late June to October is peak: warm water (often 70°F / 21°C or above), reliable sunshine, and busy beaches and harbour. School-holiday weekends in July and August are crowded; midweek visits are easier. September and early October are arguably the best — water is still warm, the marine layer that often greys out June mornings has lifted, and crowds are thinner.
November to April is cool but mild (highs 60–70°F / 15–21°C). Water is too cold to swim without a wetsuit, but this is the prime whale-watching season — grey whales migrate close to the coast December through April, with peak sightings in February and March. Boats run year-round; in summer it is dolphin pods and blue whales further offshore. May and June can bring 'May grey' and 'June gloom' — overcast mornings that burn off by lunch, sometimes not at all.