The Bon festival takes place every year from August 13th to 16th. It is a Buddhist festival held to welcome back the spirits of the dead. Many people receive company holidays during the Bon period and go back to their hometowns or go to a summer vacation. So, TDR is heavily crowded at that time.
I was unknowingly in Tokyo during that time a few years ago. I didn't understand it. I had gone to TDS on Friday to what I thought were reasonable crowds for a summer week day. I went to TDL the following Monday and saw a HUGE throng of people. I waited 30 minutes at opening for a Pooh FP. All FPs disappeared by about 11 am. The place was packed. I noticed a girl spoke English to me as I walked by her as she extended the HM queue right after park opening. She explained that it was a holiday for all of Japan. Go figure.
BUT, I still had an amazing time. Rode all the biggies except Jungle Cruise and some others. Sitll hit the Mountains, and even scored a second standby Pooh ride during the ELP, since everyone was watching it.
And I concur with the heat comments. You can fit in with the locals and bring an umbrella for shade.
Thanks for the responses. I've already been to Tokyo in early August. It's hot, though not as hot and humid as Shanghai, that's for sure. An umbrella ( or should I say parasol) to keep off the sun takes care of most of the discomfort.
If I can go this summer, I will definitely avoid that week.
It never occurred to me, as a man, to carry an umbrella. I assumed it was just to keep the sun off your face. Does it really help with the heat that much? And does it need to be a black umbrella, which absobs the heat, or a white umbrella, which does not? Or does it make no difference?