The Great Lakes and the East Coast are set to experience a prolonged period of cool temperatures extending well into the fall season. Following a notably chilly August, residents can anticipate fall-like conditions to persist across the Great Lakes region and much of the Eastern United States through at least mid-September. Daytime high temperatures are expected to run 15-20°F below the seasonal average, with an even more significant drop of 20-25°F possible during periods of rainfall.