what type of states politically/culturally would "Northern California" & "Southern California" be?

[Skill and Chance]

Do you mean if they split today or were split upon admission to the Union? 

In the former case, not much would change in the short run, but in the long run SoCal would probably resemble a socially liberal Rust Belt state like Michigan due to the outmigration and economic struggles.  It would gradually trend right and Republicans would probably do better at the state level than federally.  NorCal would be uttely locked down for Dems by Silicon Valley and would have more in common with Colorado or the NE states where a majority of young people go to college. 

In the latter case, SoCal would likely be admitted as a slave state and attract a ton of Southern migration early on.  During the Civil War, it may very well end up voting to join the Confederacy or if not, being forcibly occupied by the Confederacy for a time.  It would probably be a distinctly culturally Southern state to the present day.  IDK if L.A. ever becomes a center for film making in this world.  Maybe it still does.  Much of early Hollywood was made up of former Southerners after all.  In any event, I would expect a SoCal that diverged pre-Civil War to vote Dem until sometime in the mid 20th century and then GOP after that, with Dems possibly gaining strength again very recently as in Arizona, which was the most Southern/Confederate-influenced Western state IRL.