The White House press office determines when to call a full lid, signaling to the pool that the president has no further public events, travel, or announcements for the day. This decision typically tracks the official schedule, which for the week of May 18–23 centers on routine Executive Time, policy meetings, and in-town pool coverage with limited open-press items. Recent patterns show early lids issued on days without major bilateral engagements or legislative activity, while developments such as sudden diplomatic statements, congressional votes, or national security updates can extend press availability past 6:30 p.m. Traders monitor the daily pool reports and any changes to the president’s calendar, as quiet periods following events like the May 17 National Prayer gathering often produce earlier closures.