Blessed by weather and geography, California was poised to reap billions of defense dollars. California went from a primarily agricultural economy in the 1930s to one of defense related activities and industries. The weather allowed for military training year round and resulted in a disproportional amount of military bases.
This resulted in a boom in the construction industry, which in turn provided many new, highly paid civilian jobs. The civilian population went from 6,950,000 in 1940 to 9,344,000 in 1945. Despite tight wage and price controls imposed by the federal government, California prospered during the war. With the end of "the War," California's economy continued to grow.
Many of the new industries transitioned to making consumer goods. The aerospace industry became a major employer. The "GI Bill" resulted in an expansion to California's colleges and universities as well as a major housing boom. Then came the "Baby Boom."