Most of my riding is XC and I tend to get quite hot when I'm riding. Ordinary winter stuff like softshells or merino baselayers are pretty much for snow and ice for me.
I really like my castelli nano arm and kneewarmers so what I really want is a good warmer short sleeve jersey. Sort of thing I'm after is gore contest thermo style weight. Anyone do such a thing or are all short sleeve jerseys thin?
The Rapha ones are thicker/heavier. Also Torm, not sure about Shutt VR
dhb windslam, light weight but windproof
gabba jersey to match the arm warmers?
If your rich see the Embers short sleeve in fresh goods, thicker than normal tops
I've had pretty good results by adding a mesh vest under my xc shirt for racing when it's around 5 degrees C
You can get some dodgy search results when googling men's mesh vests though!
This one's safe though and fit is good
http://www.wiggle.co.uk/craft-cool-mesh-superlight-sleeveless-base-layer/
Next level up is two xc shirts