Depending on your preferred definition, summer ends on the 31st of August (meteorological), on the fall equinox (astronomical), or on Labor Day in the USA (the rest of us). The fall equinox occurs on September 21, give or take a few days. This year (2017), we experienced a very dry September with some record breaking heat.
Some trees were beginning to change color.
I found this shell on a bridge over the DuPage River.
Young Mallard
Asters bloom near the end of the summer.
Dragonfly - This is a Widow Skimmer - probably male.
This Maple leaf was turning yellow by losing its chlorophyll.
A different Maple tree - this time a Freeman Maple. Freeman Maple leaves may turn
either yellow or red or both.
Freeman Maple leaves.