This jacket keeps you warm and LITERALLY WICKS YOUR SWEAT OFF, keeping you cool on days you want to be cool, and warm when you want to be warm! i ran a mile on an all-uphill trail and didnt feel any sweat at all (it was around 50-60 degrees)! on the mountain, it keeps you insanely warm too! i rode mt. hood over the summer and it kept me warm, but cool (it was around 65-75 on hill)! it was GREAT! looks great, functional, versatile, everything you'll ever need in a jacket! hopefully i'll get it in black too. i have the blue and green already!