Yesterday we set a record-high temperature: 34°C at O'Hare. Even with the lake-side cooling we had downtown, it still sucked. Today, however, a cold front is slowly marching across the prairie and the temperature is forecast to fall to 13°C overnight.
Good timing. The September equinox is tomorrow night. So even though meteorological autumn began on the 1st, it's nice that astronomical autumn will begin right on time.