The closely matched trader probabilities for 70–75% and 75–80% turnout in Peru’s June 7 presidential runoff reflect expectations anchored to the first-round figure of 73.81% among 27.3 million registered voters, where mandatory voting applies but enforcement and participation patterns vary by region. With Keiko Fujimori and Roberto Sánchez confirmed as finalists only three weeks prior, the brief campaign window limits mobilization efforts that could otherwise drive higher participation. Recent polling shows a narrow contest sensitive to turnout differentials between urban conservative bases and rural or leftist-leaning areas, while historical second-round patterns in Peru’s polarized contests have produced similar ranges absent major disruptions. Late developments such as intensified get-out-the-vote drives or weather events could still shift outcomes within this window.