A helpful hint for all mayors: If you make a mistake, own up to it and move on.

That's what Mayor Bill de Blasio did Tuesday -- and instead of looking like an embattled, misinformed churl, he came out looking like an honest man.

That's not an everyday sight at City Hall.

At a news conference yesterday morning, the mayor was pummeled by an army of reporters about the miserable snowed-in conditions on the Upper East Side.

Why was the neighborhood still a mess? Where were the snow plows? Was the neighborhood slighted because it's the pricey home turf of the tony 1 percent -- when they're not basking in Bermuda or Ibiza?

De Blasio stood firm.

One hundred percent of the city's primary streets have been plowed, he insisted -- and no, there was no attempt to penalize the Upper East Side.

As it turns out, there was never a good reason to suspect a plot of vengeance against the neighborhood.

For one thing, this isn't New Jersey -- and we're not talking about access lanes to the George Washington Bridge.

For another thing, the mayor apparently had second thoughts about his media comments. Later in the day, he went uptown to see the Upper East Side for himself. What he discovered was a neighborhood still digging itself out.

"While the overall storm response across the city was well-executed, after inspecting the area and listening to concerns from residents," de Blasio said, "I determined more could have been done to serve the Upper East Side."

Suddenly it's a strong moment for de Blasio.

Compare. When the city was caught short in a blizzard three years ago, Mayor Michael Bloomberg angrily snapped: "The world has not come to an end! The city's going on!"

Then there's John Lindsay. When a blizzard hit the city and took scores of lives in 1969, eastern Queens remained paralyzed for days. Photos of a beleaguered mayor facing a sea of furious faces became a national symbol of failure.

This time, the city fell short -- but de Blasio recovered.