I prefer taking early morning brisk walks when the air is more fresh and the environment is cooler than it is in the late afternoon. Well, unless it is fall and winter time when it is chilly early in the morning and practically any time of the day.
During summer and springtime when early mornings are cool, I just wear my regular hoodies or gym jackets to keep me comfortably warm. That, and a pair of light mittens when the air is a bit chilly in springtime. Nowadays when the temperature is lower, I have to layer or wear thicker clothing when I go out early in the morning. One day, I was in a "window shopping mode" for sports gear and I discovered the north face jackets. They're perfect for my outdoor jaunts especially on this cold season. The material is lightweight but strong enough to keep me warm even on very chilly mornings. Oh, yes, they come in a variety of great colors and designs, too.