Polling sites are open today from 7 a.m. to 6 p.m. as people across the state vote on legislative and Congressional seats, county councils and mayors on O'ahu, Kaua'i and the Big Island.

Although polls close at 6 p.m., people standing in line then will still be able to cast ballots.

Election officials encourage people to vote during the nonpeak hours of 9:30 to 11 a.m. and from 1 to 4 p.m. today.

Because today is a primary election, voters will mark their ballots by which party primary they want to participate in, then can vote only for that party's election contestants. However, some of the other races are nonpartisan, such as each county's council and mayor races, and every voter regardless of party affiliation can vote in those races.

During the Nov. 4 general election, voters will be able to vote for the U.S. president, candidates for Office of Hawaiian Affairs and proposed amendments to the state Constitution and county charters.

For today's primary election, voter registration is up just 1.8 percent statewide from two years ago, and elections officials predict that about 40 percent of voters who participate in the primary will cast ballots via absentee or walk-in voting.

Results of early walk-in voting were down this year, suggesting that fewer voters overall will turn out today.

Only 13,027 early walk-in votes were cast on O'ahu, about 4,000 fewer than in the 2006 primary.

Kaua'i had 2,841 early walk-in ballots cast; Maui, 2,537; and the Big Island had 8,374.

Most of the results of "absentee mail ballots" will be reported tonight in the first set of election returns, said state voter services coordinator Rex Quidilla.

Island-by-island turnout, however, may be higher because of the mayoral campaigns. On the Big Island, for example, voter registration is up 6 percent.

On O'ahu, the big question is whether voters will re-elect Mayor Mufi Hannemann tonight or cast enough ballots for his two top opponents — Ann Kobayashi and Panos Prevedouros — to force a runoff in the Nov. 4 general election.

To win outright tonight, Hannemann would have to receive more than half of the votes.