Somehow Singapore being 1 degree from the Equator manages to have a bus network, a metro and practically caps the amount of cars on the roads.

Also, you seems to underestimate how bad the weather in Amsterdam is. Cycling on a bridge through rain against the wind at 5 degrees (C) isn't very fun either.

When I lived in a more hotter climate, 30ish (C) was a-okay for some people to cycle to work and then get a shower at work. It's all about infrastructure really --- be it showers, speed limits or bike paths.