Conventional wisdom says few voters will go to the polls on Tuesday, on a summertime Election Day a week before the first day of school while many families will still be on vacation.

But 10 percent of Miami-Dade’s registered voters have already cast ballots in the primary election — most of them by mail, despite an ongoing absentee-ballot fraud investigation marring some local races.

Two Hialeah absentee-ballot brokers have been charged over the last two weeks with voter fraud for allegedly filling out ballots against voters’ intentions and, in at least one case, forging a voter’s signature. The brokers, known as boleteros in Spanish, have yet to be linked directly to any campaign, though the cases have indirectly touched the county mayor, the state attorney and a county commissioner.

The number of absentee and early votes is higher than in the last comparable primary in 2008. Yet that doesn’t mean turnout will be higher when the polls close Tuesday.

In recent years, more and more of Miami-Dade’s 1.2 million voters have cast ballots before Election Day. So while the number of absentee and early votes may be higher, the number of voters going to their precincts may not follow suit.

“There seems to be an increased interest in voting before Election Day,” said Carolina Lopez, a spokeswoman for the Miami-Dade elections department.

Of the nearly 165,000 Miami-Dade voters who requested to vote absentee this election, more than 85,000 had returned their ballots to the elections department as of Monday. More than 38,000 additional votes were cast over the week of early voting that ended Saturday.

Among Broward’s more than 1.1 million voters, more than 16,000 voted early. The number of absentee ballots requested and returned was not available from Broward’s elections department.

Polls in both counties will be open from 7 a.m. to 7 p.m. Voters should bring a photo identification with their signature, such as their driver’s license, to the precinct assigned on their voter information cards. Because of once-a-decade reapportionment, many voters will be casting ballots for races in new districts than in the past.

Absentee ballots are counted only if received by elections officials by 7 p.m. Tuesday. Completed ballots can be hand-delivered to elections headquarters, but not at voters’ precincts. If voters show up at their precinct with an absentee ballot, they will be asked to discard the absentee ballot and fill out a regular, Election Day ballot instead.

The races on the ballot range from U.S. Senate to Florida House to county commission, depending on a voter’s district and party affiliation. Many contests — particularly in Broward, where the sheriff, clerk of the courts and county commission races are partisan — are closed primaries open only to Republicans or only to Democrats.

Among them are Republican and Democratic primaries for U.S. Senate, expected to be easily won by U.S. Rep. Connie Mack IV and incumbent Sen. Bill Nelson, respectively; a Republican primary to pick a candidate to challenge Democratic U.S. Rep. Debbie Wasserman Schultz, of Weston; a Democratic congressional primary between West Palm Beach Mayor Lois Frankel and Broward County Commissioner Kristin Jacobs; and a slew of Florida House and Senate contests.

A congressional primary between U.S. Rep. Frederica Wilson and challenger Rudy Moise, both Democrats, will be open to all voters because no other candidates have filed to run in the November general election. The district straddles Miami-Dade and Broward. Another primary between two Democrats vying for a Miami-Dade/Broward district, state Rep. Joe Gibbons and rival Sheldon Lisbon, will also be open to all voters.

In Miami-Dade, the most prominent contest open to all voters, regardless of district or party affiliation, is for the nonpartisan county mayor. Mayor Carlos Gimenez, elected last summer to finish the term of ousted Mayor Carlos Alvarez. Gimenez is now seeking a full, four-year term. He faces six opponents, chief among them County Commission Chairman Joe Martinez. There are also nonpartisan commission races in five districts, a School Board race in one district and a number of countywide judicial races.

In Broward, voters countywide will vote for two, at-large School Board members, as well as for three district seats. There are also countywide races for circuit and county judges.