The real Nebuta happens in Aomori at the start of August. Shibuya Nebuta is on a much smaller scale with just a few of the floats from the Aomori event paraded (much more sedately than they are in Aomori) along Shibuya’s Center Gai.
Info on the event is scant, but the nebuta floats are lit up from the inside, so the parade will take place in the early evening.
Organizers may cancel events, alter schedules, or change admission requirements without notice. Always check official sites before heading to an event.