Just over 30 percent of Orange County’s 1.6 million registered voters cast ballots in the June 8 primary, according to the final vote count, which will be certified tomorrow.

The local turnout mirrored the statewide pattern — just 31.2 percent of all California registered voters either went to the polls or turned in an absentee ballot.

Primary elections tend to have a lower turnout than the November general elections, but Neal Kelley, Orange County registrar of voters, said the rise in vote-by-mail ballots over the past few years makes the turnout for this fall’s contests more unpredictable.

In the past four years, he said, the number of Orange County voters casting absentee ballots has gone up by 80,000.

“We’re likely to see almost an even split between the two” methods of voting in November, Kelley predicted.

This mont,h voters who had requested vote-by-mail ballots surprised local election officials by turning in record numbers of them at the polls on Election Day.

Kelley isn’t sure why 53,000 voters waited so long. But anecdotally he’s heard a number of times that “a lot were waiting to see what transpired in the (Republican) governor’s race down to the last minute.”

Kelley will officially certify the Orange County tally tomorrow after making his report on the election to the Board of Supervisors.

Among the most contested races, Fullerton City Councilman Shawn Nelson was elected to fill a seat on the Board of Supervisors left vacant by the election of Chris Norby to the state Assembly.

Nelson defeated a field of five challengers, including Anaheim City Councilman Harry Sidhu, but didn’t capture more than 50 percent of the total vote. Nelson and Sidhu, who was runner-up, will face off in November for a new four-year term.

Similarly, Deputy Treasurer Keith Rodenhuis will face Huntington Beach Treasurer Shari Freidenrich in a November runoff. But Sheriff Sandra Hutchens won her seat outright with 52.7 percent of the vote.

— TRACY WOOD

Join the conversation: In lieu of comments, we encourage readers to engage with us across a variety of mediums. Join our Facebook discussion. Message us via our website or staff page. Send us a secure tip. Share your thoughts in a community opinion piece.