There is no bank holiday in June.
For students, it's before the summer vacation.
It means, other than weekend, people don't have any days off.
What's more, in Tokyo, it rains a lot during the rainy season, which normally starts in the beginning of June and ends in the middle of July.
This year, the rainy season has already started in Tokyo. Women around me (mostly editors working for publishers) are talking about buying a new umbrella and a new pair of rain boots... actually it sounds kind of fun.
Even on a rainy day, it's important to find something to make you happy;)