This Presidential Primary coincides with a state/local primary. These coinciding primaries tend to have an impact upon voter turnout.

Tuesday 7 June 2016 (presumably): California Primary. Hours 7:00a-8:00p PDT (1400-0300 UTC). Delegate Selection: Winner-Take-All (district and statewide) Primary. Voter Eligibility: Closed Primary.

Primary
Source: California Secretary of State.
Status: Official. Retrieved: Thursday 21 July 2016.
Included in Nationwide vote.

Tuesday 7 June 2016 (presumably): All 172 of California's delegates to the Republican National Convention are pledged to presidential contenders in today's California Presidential Primary.

• 159 district delegates are to be bound to presidential contenders based on the primary results in each of the 53 congressional districts: each congressional district is assigned 3 National Convention delegates and the presidential contender receiving the greatest number of votes in that district will receive all 3 of that district's National Convention delegates.
• 13 at-large delegates (10 base at-large delegates plus 0 bonus delegates plus 3 RNC delegates) are to be bound to the presidential contender receiving the greatest number of votes in the primary statewide.

The selection of Presidential Nominating Convention Delegates to the Republican National Convention ... shall be chosen by the Presidential candidate who obtained the plurality of Republican votes within each Congressional district, and, for ... at large ... by the Presidential candidate who obtained the plurality of Republican votes statewide. [Standing Rules and Bylaws of the California Republican Party As Amended 20 September 2015 Article VI Section 6.01 (A)]

Primary
Source: California Secretary of State.
Status: Official. Retrieved: Thursday 21 July 2016.

In addition, 3 party leaders, the National Committeeman, the National Committeewoman, and the chairman of the California's Republican Party, will attend the convention as pledged delegates by virtue of their position.

California Republican Party Chair – Senator Jim Brulte
Republican National Committeeman – Shawn Steel
Republican National Committeewoman – Linda Ackerman

Individual CD and At-Large delegates are chosen by the Presidential candidates.

Each delegate to the Republican National Convention shall use his or her best efforts at the convention for the party's presidential nominee candidate from California to whom the delegate has pledged support until the person is nominated for the office of President of the United States by the convention, receives less than 10 percent of the votes for nomination by the convention, releases the delegate from his or her obligation, or until two convention nominating ballots have been taken. Thereafter, each delegate shall be free to vote as he or she chooses.... [California Elections Code Section 6461.(c)]