No question that political boundaries don't match up with climatic boundaries. That makes making a regulation covering the age of tires and selling used tires very difficult. Not to mention the political climate! (Did you see what I did there?)
Studded tires are legal anywhere in California between certain dates and when the CHP Commissioner determines they should be allowed. Of course the large majority of Californians live in areas where snow/ice is a once in a generation event, but the law stands to cover the areas where it might be needed.
The rules on VOC content in windshield washer fluid varies by county, and sometimes even within a county. The two population centers in El Dorado County are South Lake Tahoe and El Dorado Hills. They're about 80 miles apart. South Lake Tahoe is at about 6000 ft and sees snow every single year. El Dorado Hills is at about 800 ft, is considered part of the Sacramento area, and snow there would be a freak thing. So it's split up depending on where the location is. I don't know how they enforce it though.