An unauthorized fire hydrant opening offers temporary relief from extreme heat for children in Milwaukee, Wisconsin, U.S. June 29, 2026. Angela Peterson/USA Today Network via REUTERS. HILL CITY, Kansas/CHICAGO/NEW YORK, July 1 - Record-breaking temperatures spread to the eastern U.S. from the Midwest on Wednesday, putting tens of millions of people under heat warnings expected to last into the July 4 holiday weekend, when Americans will celebrate the nation's 250th anniversary.