1) I've rarely seen a pair of denim capris look flattering on anyone; they look like ill-proportioned jeans. See examples below.
2) If you are hot in jeans, you will be hot in denim capris. Exposing an extra foot of flesh on each leg while still swathed in heavy, tightly woven denim will not do much to cool you down.
3) Denim capris strike me as a very "mom" wardrobe choice, and not in a good way.
4) An especially odd practice is rolling up regular length jeans to become capris. It is a terrible idea. You're not fooling anyone. The giant cuffs look heavy and clunky around your calf, which happens to be the thickest part of your lower leg, which is made to look thicker with the fatty cuff wrapped around it. And generally speaking, capris tend to "cut" the leg, meaning they make the leg look shorter by cutting the visual continuity of the leg.
But if capris are a wardrobe staple, remember that capris also come in an array of other summer-appropriate fabrics. And don't forget your other summer options: loose pants, walking shorts, skirts, and nudity*.
*To avoid arrest for indecent exposure, use the nudity option only when and where appropriate.