With its vast and diverse coastline, there aren't many better places to go whale watching than in California . Few experiences are as mind-boggling as finding yourself feet away from the most massive mammals on planet Earth—but what you'll see among the waves depends on a few key factors, namely where and when you go. "The most successful wildlife trips follow animal patterns and seasonality," says Condé Nast Traveler Top Travel Specialist Josh Geller of Embark Beyond . Gray whales head southward down the coast during winter, in a journey that happens to be the longest migration of any mammal on the planet. Moreover, you might get lucky and see some fin, humpback, or minke whales during that time. In spring, the gray whales head north again, fin whales become more abundant, and orcas populate Northern California waters. Come summertime, the blue whale dominates the deep waters off Southern California. In the fall, attention shifts to the humpbacks in the south and back to the orcas around Monterey.…