A: Jay from Capitola asked, "what is considered 'Southern California,' 'Central California' and 'Northern California?' What cities are the cut-off point? For example, is Santa Barbara considered part of 'Southern California?' Where does one section begin and the other end as far as cities?"
Here's Chief Meteorologist Norm Hoffmann:
After doing a little research, I decided the best place to start would be to define the Central California Area and then the Northern and Southern California would fall into place.
Central California can have widely varying definitions depending on the context. Some divide the state by lines of latitude making northern, central and southern sections. Others divide by county lines or watershed boundaries. Some definitions include more of the San Joaquin Valley and even larger portions of the Central Valley. Some have less or none of Central Coast.
Central California, sometimes referenced as Mid-State, is an area of California south of the San Francisco Bay Area and north of Southern California. It includes the southern portion of the San Joaquin Valley south of the San Joaquin River Delta, the Central Coast and central hills of the California Coast Ranges, and the foothills and mountain areas of the central Sierra Nevada.
Generally the widest definition of Central California is the middle third of the state by latitude. The southern boundary of that area would be 35° 41', which nearly coincides with the county lines already used for the southern boundary that cross the state west-to-east below Monterey, Kings and Tulare Counties. The northern boundary of that area at 38° 51' crosses just north of the Sacramento metro area. However, the San Francisco Bay, Sacramento and Stockton metro areas are traditionally considered parts of Northern California, intuitively grouped together as the northern urban center within the state. That leaves the most accepted definitions of Central California to the areas south of there. I have attached a copy of the County Maps.
So the areas to the north would be Northern California and the area to the south would be southern California. When I was in the National Weather Service we defined the terms Hydrologically. That would be Northern California from SFO Bay across the state on I80 and I50 northward. Mainly the Watershed for the Sacramento, Eel and Russian River. Lake Tahoe was considered Northern California. The watershed for the San Joaquin River would be Central California which went to the Tehachapi Mountains and also split Santa Barbara County from the Santa Ynez Mountains north with a line over to the Tehachapi Mountains then across Inyo county. That put Santa Barbara in Southern California, but Santa Maria in Central California.
So you get the idea there are varying definitions, but the state can be divided by Latitude, Hydrologically or by Commerce.