"Bloomberg's decision came just a day after he appealed to the grit and resiliency of New Yorkers, saying, "This city is a city where we have to go on."
Mary Wittenberg, president of the New York Road Runners, the group that organizes the marathon, said canceling was the right move.
"This is what we need to do and the right thing at this time," she said.
"It's been a week where we worked very closely with the mayor's office and felt very strongly, both of us together, that on Tuesday, it seemed that the best thing for New York on Sunday would be moving forward. As the days went on, just today it got to the point where that was no longer the case."
Patrick Lynch, president of the Patrolmen's Benevolent Association — the police department's largest union — called the decision to cancel the marathon "a wise choice."
ING, the financial company that is the title sponsor of the marathon, said it also supported the decision to cancel. The firm's charitable giving arm has made a $500,000 contribution to help with relief and recovery efforts, and is matching employee donations.
Wittenberg said about 10,000 runners were expected to drop out after the storm arrived.
For now, marathon organizers are sticking to their policy of no refunds for runners, but they will guarantee entry to next year's marathon. However, Wittenberg said the group would review the refund policy.
Eric Jones said he was part of a group from the Netherlands that collected $1.5 million to donate to a children's cancer charity if the runners competed.
"We understand, but maybe the decision could have been made earlier, before we traveled this far," said Jones, whose group came to New York a day earlier.
Steve Brune, a Manhattan entrepreneur, was set to run his fourth New York City Marathon.
"I'm disappointed, but I can understand why it's more important to use our resources for those who have lost a lot," he said.
Brune said he thinks foreign runners who traveled for the race will be even more disappointed.
"When you have a significant amount of people voicing real pain and unhappiness over its running, you have to hear that. You have to take that into consideration," said Howard Wolfson, deputy mayor for government affairs and communications.
"Something that is such a celebration of the best of New York can't become divisive. That is not good for the city now as we try to complete our recovery effort, and it is not good for the marathon in the long run," he said.
Earlier in the day, race preparations seemed under way as normal.
White tents where the runners would meet were already erected. Plastic crates lined the park's wall for two blocks, with tangles of electric wires and other setup equipment where workers buzzed around. A few TV news crews set up camp.
Along the race route in Queens, a couple of marathon banners hung from street lamps.
"I'm not a fan of what he's doing," Manhattan resident Michael Folickman said of Bloomberg's decision. "I think that if the bridge is cleared and the streets are clear, I don't think it'll wreak any more havoc than what's already been wreaked."
"And I think it could be an uplifting experience for the city to have something exciting like that happen on top of this terrible hurricane," he said.
In Staten Island, Eddie Kleydman said the marathon wasn't important amid all the storm's devastation.
"Look at this," he said, motioning toward the huge piles of discarded furniture and household items that line his street. "Who cares about the marathon? We need garbage trucks, we need FEMA to act quicker. He's worried about the marathon; I'm worried about getting power."
At the midtown New Yorker Hotel, Gisela Clausen of Munich, Germany, told her fellow runners about the cancellation as they walked in.
"You don't understand. We spend a year on this. We don't eat what we want. We don't drink what we want. And we're on the streets for hours. We live for this marathon, but we understand," she said.