"There is a truly awesome number of people here and we have come to join them to celebrate our Christianity in the most universal and Catholic sense," said Joe Melendrez, a rap artist from San Antonio, Texas.

The crowd erupted in cheers when Benedict arrived at nightfall, greeted by Spain's crown Prince Felipe and Princess Letizia. Once it became clear he couldn't proceed with his speech because of the storm, organizers told the crowd that they had asked for more water during the day when it was so hot, and their prayers were answered.

"With this rain, the Lord sends us many blessings," Benedict quipped when he resumed his truncated remarks.

Vatican spokesman the Rev. Federico Lombardi said that when the storm kicked up, Benedict had been asked by his aides what he wanted to do and he insisted that he wanted to wait the storm out. The half-hour delay, he said, was due mainly to the failure of the sound system; once it was fixed and the storm passed, Benedict proceeded with the vigil program.