California is in two hemisphers: northern and western. A hemisphere is half of a ball, so the earth can be cut in half either of two ways:
North & South -- above and below the equator; East & West -- hmmm... this gets tricky because of politics. Generally, the divide between east & west runs through Istanbul (originally named Byzantium and later Constantinople), a major city in Turkey, and "somewhere" out in the Pacific Ocean.
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The hemisphere that is south of California is the Southern Hemisphere.
California is located in the northern hemisphere.
California is in the northern hemisphere :P
Western Hemisphere
Baja California is in the Western Hemisphere.
Baja California is in the Western Hemisphere.
You live in the Northern Hemisphere if you live in California.
California is in the northern hemisphere, as it is North of the Equator. And is in the Western Hemisphere, as it is to the West of the Prime Meridian.
California
ITs in both
Northern Hemisphere
The Southern Hemisphere is south of California.