Don't think you'll get a reliable answer on the internet... depends on whether you feel the cold and what kind of pace you ride. For all the people saying they only get it out when it's under 5°c and wear it with a thin baselayer, there are others who feel the chill and like to layer.
(right now I'm sitting indoors wearing two merino t-shirts, a wool jersey, a scarf and a rapha softshell. I expect I'd overheat fairly quick on the bike but I'm still cold now... and overheating for me will mean taking off my scarf and dropping the hood of the jersey)
Don't think you'll get a reliable answer on the internet... depends on whether you feel the cold and what kind of pace you ride. For all the people saying they only get it out when it's under 5°c and wear it with a thin baselayer, there are others who feel the chill and like to layer.
(right now I'm sitting indoors wearing two merino t-shirts, a wool jersey, a scarf and a rapha softshell. I expect I'd overheat fairly quick on the bike but I'm still cold now... and overheating for me will mean taking off my scarf and dropping the hood of the jersey)