Dolphins live all along the Monterey Bay, I've seen them several times by the coast in various areas ranging from Bixby Bridge to Sand City. Closest I saw them was when they swam right up to the shore in Carmel beach in the late summer.

I went to college in Santa Cruz and grad school in Monterey… there really isn’t a particular season for dolphins since they live in the bay and along the coast. I think I saw them most frequently in the spring, but that could also be because the weather was nicer so I was outside more. 😉