Watching the floats on Market Street in San Francisco, Michael and Tom Crawford, both 52, recalled their marriage in 2004, after Gavin Newsom, then the mayor, had authorized same-sex weddings in the city. Soon after, the state’s Supreme Court invalidated the union. The pair moved to Massachusetts and married there before returning to California in time to see voters pass a proposition banning same-sex marriage in 2008.

“I feel like a full citizen for the first time in my life,” Michael Crawford said. “And I feel that people that still hate no longer have the government backing them up.”

Other cities, including Chicago and Seattle, also hosted parades on Sunday. Across the country, organizers and officials braced for large crowds, though at least in New York, the parade — never dull even in less eventful years — has been blessed by particularly good timing before.

In 2011, it came just after New York State legalized same-sex marriage. In 2013, it was held days after the United States Supreme Court ruled that married same-sex couples were entitled to federal benefits.

“Odd-numbered years we do well,” James Fallarino, a spokesman for the parade, said.

One of the organizers, Chris Martin, said there were about 20 volunteers earlier last week to help inflate balloons. After the Supreme Court decision, his Facebook page was inundated with requests to be included.

“People were saying, ‘Add me, add me,’ ” he said.

By midmorning Sunday, scores of helpers had inflated more than 700 balloons, color-coordinated in sets of 20.