Presidential primaries are elections held by political parties in the United States to select their candidate for the presidency. During these elections, party members vote for their preferred candidate, and the results help determine how many delegates each candidate will receive for the party's national convention. There are two main types of primaries: open primaries, where any registered voter can participate, and closed primaries, where only registered party members can vote. The primary season typically begins in early election years and plays a crucial role in shaping the political landscape leading up to the presidential election.