Having been to Amsterdam just last week I was really surprised by a) the weather (it rained intermittedly every 1-2h) and b) that only a small percentage of the cyclists seemed to be prepared for the rain.

I cycle to work most days in Munich, so the climate is roughly the same, and I have rain gear and I'm used to cycling in the rain... I couldn't imagine cycling with an umbrella, but that's a different story... Maybe I was just getting a cold, but I was freezing while being soaked just walking around in the city (with my rain jacket, didn't bring the rain pants).