There is that particular time of the year when the temperature is just right: when the early morning hours require a light jacket, then after sun up one can sit outside until around 11:00 a.m. and be comfortable in short sleeves and either pants or shorts. I suppose shoes could be optional depending on where one lives.
This time in between seasons happens twice a year where I live and doesn't last long. Perhaps a few weeks, a month if I'm lucky. It's a time when I look forward to yard work, and the breaks in between chores. This is also a time Frosty the dog seems to look forward to as well; as it means more outside time with his people.
The larger birds drift over head on the air currents and the insects that tend to be a bother are minimal. A cool breeze bends the grass and trees a little, and It's the perfect time of year to catch a good sunrise or sunset. The existence of clouds can make for a better scene to me; something to be said for the hues of color coming from the sunlight reflecting off of them in those early morning and late evening hours.
I enjoy listening to the crickets and the fish jumping for a meal during these times of day. Seeing the dragonflies that look nothing like dragons but do resemble helicopters when the angle and light is just right. Hearing the waves of birds voices waking up, that's the real treat.
I suppose all cells of life have a point where the metabolic flow of energy is balanced. Perhaps it is so that consciousness arises from the interactions of a multicellular existence...that which keeps the structure together and regulated from birth to death. If so, then such a state would have fractal reflections in the mind and could explain why I feel so good at these two particular times of the year.
The end of Summer or the beginning of Spring, I'll take either one. If only such temps existed in the same place all year long.