Mother Nature once again graced the city with gorgeous weather for the 9/11 memorial ceremonies — yet Hillary Clinton was somehow overcome by the mild, low-80s temperatures, and left early in obvious distress.

Clinton’s health is no longer a background issue in the presidential race.

The footage of her entry to her ride out is especially troubling: She’s leaning oddly backward as she waits, and plainly almost collapses as she moves toward the vehicle; a mob of aides then conveys her inside.

Also telling is that her staff avoided alerting the press that travels with her — and were left to catch up after noticing her missing. Clinton’s brief walkabout some 90 minutes later, after she’d rested in daughter Chelsea’s apartment, settles nothing. Nor does word late Sunday that she has pneumonia.

We hadn’t made much of Clinton’s long coughing fit last week, but that now seems more disturbing, too. Maybe her repeated memory failures when the FBI interviewed her over her email abuses were actually real, rather than dodges of questions she didn’t dare answer truthfully.

Even her refusal to hold a single real press conference for more than nine months suddenly looks different: Is she dodging the press to avoid questions about all her endless scandals, or does she fear something else?

Behind it all is the concussion she suffered in late 2012, which led to a blood clot in her head — an illness that prevented her from doing more than token work in her final months at State, and also (she said) left her temporarily unable to testify before Congress on the Benghazi disaster. Her husband later said her recovery took a full six months.

At 68, Clinton is two years younger than her opponent, Donald Trump — but he’s had nothing like any of these episodes, despite more than a year of nonstop travel and public appearances. She’s now got a whole new host of questions to answer — and so do her doctors.

Credit: Zdenek Gazda