I think a lot of Euros misunderestimate (to quote Dubya) how much more extreme North American city climates are. Using wikipedia data, Amsterdam's lowest mean temperature month is January at 3.8C, and highest mean temperature month is July at 18.1C. Chicago has 3 months below 3.8C per year, in fact it's below 0C for 3 months. Plus 4 months above 18.1C. Some of our climates just aren't terribly comfortable for biking here. NYC is not much better either.