Noglider - I just got back from a 10 mile hilly ride with air temp about 45 degrees and wore a poly tee shirt, the Atom jacket and my showers Pass Shell. This was probably the upper air temp limit for what I had on but was okay. I noted a bit of my riding technique for how to regulate temp and realized I do a few things in how I ride to make temp adjustments. I had my outer shell zipped to about 4 inches below the bottom of my breast bone and the Atom jacket zipped to about 3 inches below the top of my breast bone. I rode this way the whole time and found that in my normal riding position my arm pits are closed and my head position allows just a small amount of air flow into the jacket, When I started to get hot I dropped my head about 2 inches and flared my elbows just a bit to open my arm pits. This allowed a big gush of cool air to flow under the collar and into the jacket and across my chest and shoulders then under my arms and out the side panels of the jacket. Four of five seconds like this and I dump out a whole mess of heat and sweat and I do it before it builds up enough to get uncomfortable. I did not have to readjust any clothing the whole ride and stayed very comfortable. I had never payed much attention before but I guess this conversation made me pay a bit more attention to what I was doing subconsciously. In cooler weather I normally have things zipped up a bit more, but still find ways to adjust my position and dump heat quickly with some airflow into the jacket and under my arms. I use small movements and that under arm air flow and side vents all of the time to easily make subtle adjustments to temperature. So I guess I am saying you have to find a subtle technique to use the features of the jacket best keep your temp where you are comfortable. I hope this helps.