[throw7]

I agree with other replies: infrastructure is the deciding factor (not climate or terrain).

The way to see and understand "infrastructure" is: what if gov't was cycling-centric instead of car-centric. All the "infrastructure" you see around cars? Do that for cycles. There would be safe, separate, well-maintained, direct routes to all points, all year long, 24-7.

My own belief is that this is not possible in the U.S. without a change of culture. We can't even get respect for pedestrians... in winter here, plows will dump snow right over sidewalks (it will take days for them to be cleared if at all in some places). my 2 cents.