In California, the deadline to register for any election is 15 days prior to that election. That requirement is 15 total days, including weekends and holidays, not 15 working days. The next statewide election scheduled to be held in California is on June 7, 2016. This election will be the primary election for the 2016 presidential race. 15 days before June 7, 2106 is May 23, 2016. Therefore, the last day that a person can register to vote and be eligible to vote in the presidential primary in California is May 23, 2016.
For more information about registering to vote in California, you can follow the link below. It takes you to the voting information page of the website for the California Secretary of State. You can find plenty of information there, including information on how to register to vote.
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