You are kind of asking an apples and oranges question. Are you looking for protection or warmth? Chaps offer very little protection in a crash were riding pants typically have armor in the knees, shins and hips. I started riding again in 2008 and bought a pair of chaps. After a year I moved to riding pants for the protection. I own both a summer and a cool weather set of riding pants.
You dress for the crash.
You dress for the crash.