September temperatures in October

Following a summer of meteorological excesses—extreme heat and severe drought—Chicago’s weather has progressed into a mild and dry autumn.
Those weather anomalies, however, are much easier to bear in the fall.
When the temperature climbs 12 degrees above normal in mid October, as it did yesterday, the result is a pleasant afternoon with readings in the middle 70s. When that same anomaly occurs in mid summer, however, the city swelters with temperatures in the middle or upper 90s.
Moisture deficits, too, are less damaging to vegetation in the autumn than they are in the summer because plants are heading into dormancy.
A lingering impact of Chicago’s summer drought will be muted foliage displays on moisture-stressed area trees. Premature shedding of leaves and less vivid coloration are unavoidable results of long-term moisture deprivation.