It makes a difference where your mainland destination is.
Due east to Mexico or southeast to most of CAm/SAm, easterly or NE/SE-erly headwinds all the way.
Angling north to the USA mainland and thus changing latitude, you'd start getting a reduced headwind, and eventually a westerly tailwind, starting at about Lat. 30N ("Horse Latitudes").
Not much help to SAN, a few minutes bonus enroute to LAX, perhaps nearly half the flight to SFO or SEA.
But - that is the "big picture" average prevailing winds.
If you get an atmospheric high spinning clockwise south of Alaska as in FlightDetent's map above, you could easily end up in JammedStab's situation - more or less constant headwind components to anywhere on the west coast.