According to new census estimates, approx. 501,000 people from other states moved to CA in 2018, while 691,000 Californians relocated to other states – a net loss of 190,000. In addition, an estimated 284,000 foreign nationals moved into CA from outside the country. (Foreign out-migration numbers are not available.)
The top states for out-migration are Texas, Arizona, Washington, Nevada & Oregon, states with high-tech centers of their own and/or no state income taxes, and/or significantly lower housing costs - thus attracting working residents, local businesses, and retirees. Updated Bay Area figures are not yet available, though migration trends here have generally paralleled state trends in recent years.