In a bizarre twist, the mayor initially blamed being 20 minutes late on his boat being stuck in the dense fog that rolled over the city Wednesday morning.
But he later admitted that despite having a "lot of respect" for the families, he had a "rough night" and felt "really sluggish" in the morning.
"The fog was unexpected and did slow us down quite a bit," he said at an unrelated event later in the day. "But it’s also my fault because I was just not feeling well this morning.
"I had a very rough night and woke up sluggish and I should have had myself moving quicker."
The mayor explained that he "just woke up in the middle of the night and couldn’t get back to sleep and felt really sluggish and off-kilter this morning."
But he took "responsibility" for the lateness.
"The folks out there, obviously I have a lot of respect for and I wanted to be there with them and I was honored to be there with them," he said. "I wanted to be a part of it. But absolutely it is my responsibility."
Earlier, the mayor's office blamed the fog alone.
"Mayor de Blasio traveled to the ceremony by boat this morning and the boat was delayed due to heavy fog," de Blasio spokeswoman Marti Adams said.
Meteorologists warned Tuesday night of the fog hazard and even extended the warning Wednesday morning until 10 a.m.
On top of that, sources said that the NYPD's harbor boats, which de Blasio used, underwent tens of millions of dollars in upgrades to their guidance systems.
"You can be in pea soup and find where you are going and not miss a beat," a law enforcement source said.
Frustrated mourners rang the bell marking the time of the crash at 9:16 a.m. but the mayor arrived around 9:25 a.m., prompting some to voice their disapproval in the audience and on social media.
The mayor's public schedule said he was to deliver remarks at 9:05 a.m., meaning he was actually 20 minutes late to the event.
"It's not fair to us," said Robustian Reyes, 56 who lost his brother Robert in the crash.
Another man in the audience said: "Unbelievable man. Late, late, late," as the mayor entered the ceremony.
Miriam Estrella, 21, lost five family members when the plane, traveling from JFK airport to the Dominican Republic, crashed. She got up at 9:16 a.m. and told the audience in Spanish that the bell was going to be rung despite the mayor's absence.
"Every year Mayor [Michael] Bloomberg is here on time ready to go. He’s here 30 minutes (before) socializing with the family members, giving us all the support," said Estrella.
"And this year [Mayor Bill de Blasio] came a lot of minutes late. 9:16 is the time that our family members passed away. We’re supposed to toll the bell. We’re not supposed to wait for him to toll the bell."
Estrella confronted the mayor about his tardiness after the event. She said the mayor told her he was trying but "didn't really apologize."
De Blasio's office said the mayor took a police boat to the event because it would be quicker than traveling by motor vehicle from Gracie Mansion to Rockaway Park. It was not clear how long the trip would take by car.
The boat left from the back of Gracie Mansion — de Blasio's office said they did not have the exact time of departure — and was supposed to take 35 minutes to arrive.
Instead, the boat had to move slower than normal because of heavy fog and took 55 minutes to make the trip, the mayor's office said.
The mayor's office says they arrived at 9:20 a.m. It's unclear where the boat docked but de Blasio appeared at the ceremony around 9:25 a.m.
With an arrival time of 9:20 a.m., the boat would have left Gracie Mansion at 8:25 a.m. Even with the 35 minute trip, the boat would have arrived at 9 a.m.
Tom Kines, a senior meteorologist from AccuWeather, said a fog advisory was issued for New York City at 9 p.m. Tuesday night.
The advisory warned of "visibility of less than half a mile" and was to remain in effect until 9 a.m. Wednesday morning. Because of the extent of the fog, the warning was extended until 10 a.m. Wednesday morning.
'It means if you are driving you have to slow down," said Kines who said that warning is meant for motor vehicles and boats.
It was not clear if the police department or the mayor's office was aware of the advisory. Neither office responded to requests for comment.
It's not out of the norm for de Blasio, who says he's not a morning person, to show up to events anywhere from 20 minutes to an hour late.
But family members of Flight 587 victims were hurt.
"13 years today w. Out my mother in my life , at the memorial && this f**** Dum*** mayor bill de blasio , is showing up late," wrote @KianaFaith on Twitter.
Family members also complained about having difficulty organizing the event this year and about the lack of a Dominican flag at the ceremony which they say was present in the past.
"We feel like every year we have a lot of support— the Red Cross, roses, breakfast," said Estrella. "This year, nothing. Not even enough chairs for the family members."
City Hall released statements of support from two Latino council members. Washington Heights Councilman Ydanis Rodriguez thanked the mayor for organizing a memorial to "ensure that Flight 587 is not forgotten."
City Hall also released a statement from Belkis Lora, president of the Committee in Memory of Flight 587, who lost a brother in the crash. Lora said the "size or the look of the event is not as important for us as to have the opportunity to come together here every year."
The family members of other victims strongly disagreed. The mayor's lateness hurt even more because of how hard some family members fought to gain recognition for the tragedy with the crash occurring just two months after 9/11.
Many of the victims were Dominican and family members felt their plight was not being taken seriously enough because of that.
De Blasio's lateness brought those feelings back, family members said Wednesday.
"No, it was just a Dominican flight. It doesn’t matter," said Estrella.
Additional reporting by Ben Fractenberg