Umbrella forecast

The Japanese are a very prepared bunch of people who seem to always watch the weather forecast. If you look outside your window in the morning you will always know by the people walking by wether or not to prepare yourself for the rain. The sun could be splitting the rocks but they will still have their umbrella in tow. Now then, if you contrast this with Ireland a place that you will most likely get rain 5 days out of 7 a week... why do Irish never carry and an unbrella unless it is raining when they leave the house. Perhaps we are just a very optimistic nation, optimisim in Japan in the other hand never really exists.