On April 13, the California Senate passed SB 437. It requires qualified parties to notify the state of the identity of their presidential and vice-presidential nominees by 75 days before the general election. Depending on the calendar, this would be between August 19 and August 25 of the election year. The bill says if the party hasn’t yet chosen its presidential nominee, it must identify the “apparent” nominees.
At least one of the two major parties held a presidential nominating convention on a date after the bill’s deadline, in 1996, 2004, 2008, and 2012. In 2008 and 2012, both major party national conventions were later than the bill’s deadline. But it is generally possible to know who the conventions will nominate, before the conventions actually meet.
Current California law does not set a deadline for qualified parties to identify their presidential and vice-presidential nominees.