What do you define as being "warm enough." I'm happy to go out road riding down to about 5 degrees C, and so there haven't been many weeks in the last two years in Lausanne when I couldn't get out at least once. April and May should be prime riding months, according to the BBC website, the average daily high is 15 degrees in April in Zurich, and 19 in May.

If you want the groupset, then send me a PM soon, or I will start to advertise it more widely in a couple of weeks once I've actually taken it off of the other bike.