There was one part when he was playing a guitar solo out from the microphone, and didn't get back to the microphone in time; his voice was clear, but he wasn't quite back to the microphone. The guitar playing might've been real (I'm no guitarist, so I couldn't tell), but I know it's a nightmare to have all that sound stuff actually working in the rain.
And, because people expect lip syncing nowadays, artists will record something 'semi-live' - that is, they'll record it while doing there routine for practice, then they'll lip-sync for the final performance...