As New York's mayoral race heads to the all-important Democratic primary on June 24, Andrew Cuomo is looking to hold off a group of challengers.

New York City is using ranked choice voting in its Democratic mayoral primary election. Here's how it works: Rather than pick just one candidate, voters get to rank several in order of preference.

The race to pick the Democratic nominee for mayor ends Tuesday with primary Election Day — and so far early voting has surged to nearly twice the turnout of four years ago.