Weather: It's Sirius

From the Rockies to the Atlantic, from Boston to Birmingham, the first two weeks in July—traditional start of summer's "dog days"* were as hot as anyone could remember. Temperatures brushed past the 90° point for nine consecutive days in New York, Washington and Baltimore, twelve days straight in Denver. In St. Louis the mercury soared above 100° six days running, at one point hit a broiling—and almost unbearable—108°.

Tempers and temperatures rose together. The heat, as much as ideology, triggered Chicago's race riots, a "wade-in" in Grenada, Miss., violence at New York City's Coney Island, and a prison eruption in...