Southern California get waves all year round, but to get the best out of the coast, then there are two distinct times you’ll want to head out there. From November to February is the winter season, big swells pump out of the North Pacific and light up the whole of The Californian coast.
Southern California, with it’s more stable weather grooms these swells into clean walls. In the north are the classic points of Rincon and beaches like Silverstrand are the go. Los Angeles has some classic heavy beach breaks and more rippable ones like Surf City, Huntington Beach. Then heading towards San Diego there are classic reef breaks like Trestles.
Then there is the summer season, from June to August. Massive swells from the Southern Ocean march northward and make landfall in Southern California. They vary massively in size, and often just head high days are the best you can get, but occasionally they are huge and light up the whole coast. There is also the chance of hurricanes spinning off Mexico.