Hmm, I hadn’t really thought about the lines being climate-based. But maybe they are?
I’m Australian, grew up in the Top End and lived in Vic (Melb and Bendigo) before moving to California 10 years ago. Here, we have the political divisions, counties, which make good shorthand descriptors for regions. But overall I think the divisions are more geological.
There’s the coast, obvs, which is actually relatively similar, climatically, along its enormous length, the main reason for which is the marine layer, the fog bank that rolls inland to the coastal range most days. (That’s what waters the redwoods.)
There’s the Central Valley, the breadbasket of the country, where agriculture predominates, summers are hot and dry, and winds can be strong. Again, it’s a vast length, but it does vary in temperature from south to north.
The Sierra Nevada mountains catch the clouds. The rain and snow that falls on them eventually irrigate the Central Valley and provide drinking water for just about the whole state. There’s alpine meadows, lakes and forests on the eastern border of CA, along with high desert. Or just plain desert, when you get to Death Valley in the south.
Of course, within these regions, there’s smaller microclimates. But I think the shape of the state in cross-section is what causes the differences. Something which, as a flatlander, took a little getting used to.