This is how I know when summer is starting to wind down, no matter how hot it still is or will be in the next few weeks.
The morning glory vines are spreading like mad over the back fence, and the first blooms are opening at daybreak. I took this picture at 7am this morning as I was leaving for work. I associate morning glory flowers with late summer and early autumn. By the first of September the roadside ditches will be filled with masses of blue and purple flowers.
Not a bad way to greet a new day.