[tommasi]

I wish I could tell you exactly when the raining season is.

It used to be clear cut and was usually in May to June.

I don't know whether it's caused by Global Warming or not but it is somewhat unpredictable.

Sometimes, it rains throughout July and August and got really hot in September and October.

Anyways, if you can change your plan, why don't you wait until mid July or something and meanwhile keep track of the weather.

Summer in Japan is not exactly the most pleasant thing to go through but it is probably better than rainy days...

Good luck!!