The Republican National Committee meets in Washington, D.C., January 22-25. The committee will decide whether to change the rules for presidential primary dates. If the full committee agrees with a subcommittee, all presidential caucuses and primaries will be no earlier than March 1 (except for the four states that have permission to go earlier…Iowa, New Hampshire, South Carolina, and Florida).
The Committee may also choose a national convention date, which could be in June or, if not, probably in July. The major parties never want to have their national conventions during the Olympics, and the 2016 Olympics will be August 5-21. For each of the last three presidential elections, both major parties held their conventions after the Olympics.
The tradition is that the party holding the White House holds its national convention after the other major party. If Republicans choose early July, Democrats will undoubtedly choose late July. If both national conventions are in July, or if one is in July and the other is in June, there will probably be activity in state legislatures to move the June presidential primaries to an earlier date. States with June presidential primaries are California, New Jersey, Montana, South Dakota, and New Mexico.