For hurricanes to form and be sustained the sea surface temperature needs to be at or above 26�C, which is why hurricanes weaken and die either when (a) they hit land (no continuous supply of moisture to sustain the clouds) or (b) they move into an area of cooler seas.
The Humboldt Current (which is cool) reaches as far south as California, and thus when Pacific hurricanes move any further north than Baja California the storm weakens (and also tends to move away from the coast as Babs has already said).