What happened to rain-producing systems during June 1988?

Dear Tom,
You recently mentioned that Chicago’s sunniest June was in 1988 during the city’s epic summer of drought and heat. What happened to the rain-producing systems?
— Jim Kurman, Kenosha
Dear Jim,
There is a saying among meteorologists that “in times of drought, all signs of rain fail,” and that is exactly what happened during June and most of the summer of 1988. June 1988 recorded 88 percent of its possible sunshine, buoyed by eight days with 100 percent of possible sunshine. There were 14 days with temperatures of at least 90 degrees, including three days of triple-digit heat. Precipitation totaled a scant 1.05 inches, with measurable precipitation falling on just four days. The central U.S. was dominated by high pressure that deflected most storm systems and attendant cold fronts well to the north or south of the Chicago area.