Extreme heat is no longer an occasional disruption but a recurring threat to employee health and business performance. Yet many companies still aren’t formally assessing their workforce’s vulnerability to heat. In this issue of the HBR Executive Agenda, Talia Varley, managing director at the Cleveland Clinic Canada, explains that to prepare for these continuously hazardous conditions, leaders need to understand the risks, implement safety protocols, properly calibrate indoor environments, personalize accommodations, and stay current on tightening regulations.