Nonvenomous Considered harmless to humans. (There are no venomous snakes in California that can be mistaken for this snake, but the similar-looking Arizona Coral Snake, found in Arizona, is venomous and dangerous.)
There is regional variety in the King snake sub-species and close relatives... But the rule that yellow and red are bounded by black works on all of them. Here in Colorado we have one with a lot of red:
Jason Haas and I found this tiny Milk Snake/King Snake out to me on the way down from Tiny Tower in the Flatirons of Boulder, CO. He is coiled to strike but is not much of a threat, being the size of a pencil!