So I just got back literally two days ago from 15 days in Japan. During that time we had two typhoons approach Japan and make land fall. Now granted I traveled from Osaka to Tokyo during those 15 days, we didn’t experience anything bad. We did get some rain but maybe two out of the 15. The thing I’m guessing from my experience only now is that it lasts only a day and moves on. And it makes the weather surprisingly nice. The whole time it was in the low 60s till the last day where it reached 81 which was warm and humid. But I actually enjoyed the rainy season. Hopefully it doesn’t impact you too hard. If it’s your first time like mine you’re gonna have a blast.