Public health departments in several metro areas accelerated heat-response plans after forecasts showed an early run of high temperatures. Cities expanded cooling center hours and coordinated with shelters and community groups.

Doctors said the first heat waves often lead to preventable illness because people are not yet acclimated. Officials recommended checking on older neighbors, staying hydrated, and avoiding strenuous outdoor activity during peak sun.

Utilities, meanwhile, warned that earlier demand spikes can stress local grids. Some operators said they have scheduled extra crews to respond quickly to outages and equipment failures.