And the Living Is Easy?

"City school officials began listening to reformers around the turn of the century. Gradually, they shortened the school year by about 60 days and eliminated the summer quarter. Reformers could have instituted a long break in winter, or spring, but they picked summer for three main reasons. 1) Poorly ventilated school buildings were nearly unbearable during heat waves. 2) Community leaders fretted that hot, crowded environments facilitated the spread of disease. 3) Wealthy urbanites traditionally vacationed during the hottest months, and middle-class school administrators were following in their footsteps."

Juliet Lapidos in Slate explains why children have such lengthy summer vacations.