Grunion spawn only on 3 or 4 nights after the highest tide associated with each full or new moon and then only for a 1 to 3 hour period each night following high tide. Spawning runs typically begin with single fish (usually males) swimming in with a wave and occasionally stranding themselves on the beach.

What time do Grunions come out?

Part of Southern California's ocean heritage is going to the beach around midnight to watch the grunion come ashore to spawn. As they have for generations, grunion runs occur during a three- to four-night span following a full or new moon, as the nighttime high tide is receding, typically from March through August.

Are Grunions real?

California grunion are a species of marine fish found only along the coast of southern California and northern Baja California. They are justifiably famous for their unique spawning behavior. Grunion spawn completely out of the water and lay their eggs on many sandy beaches in California.