What season is this jacket?
MARK B This is a late fall or early spring type jacket. I would use it when temps are between 50 and 30 degrees F.
J MICHAEL C Early spring, late fall, early winter- depending on base layer. Not summer
32-55 degrees- depending on wind/sun.
ANNA C The season this jacket is best suited for would depend on the intensity of the workout and the climate in which the wearer uses it. On the NW Pacific coast that could be year round. I like wearing it when the temps drop down into the 50s.
William P I have the orange/gray which came out early Fall 2011 and into 2012. With a 150 weight wool base layer (Ibex or Icebreaker), I can wear it comfortably from 20-45 degrees F with or without wind. Below that temperature, I'd choose a Patagonia Puff or just a vest above that temperature to shield from the wind (MH also makes a great vest for this occasion). This jacket shields from the wind (front panel), wicks well (back panel and arms) and dries super fast post washings. It is reflective enough for safety and the zippers are plenty reliable and durable. The fit will be snug (or form fitting) on the body and arms, but that's what you'll want if you're running. I'm 6'2" and 175 lbs and the M fits me well. Hope this helps.