Hit the Del Mar Racetrack
Farm life isn't exactly abundant in most of the city, so the closest we can get to cow tipping is placing bets on the ponies. The second race season starts November 11th, most of the races happening Thursday through Sunday. Wear a (light) scarf to instantly get the autumn vibe. Plus it'll give you something to wave as the horses fly by.
Enjoy the beach pumpkins
Going to the beach is a fall activity for many San Diegans since the weather is hotter in October than it is in June. To really ratchet up the fall factor, check out a beach with pumpkins. Every year, a pumpkin patch sprouts up across the parking lot from Swami's beach in Encinitas. The monks from the Self-Realization Fellowship grow these gourds and spend hours carving intricate designs into them. The decorated pumpkins are put on display on Halloween in front of the temple.