What a difference a week makes.

A far cry from last Saturday’s balmy 68-degree weather that brought shirtless revelers to Central Park, the Big Apple could land up to three inches of powder in the afternoon, starting at around 1 p.m., with temperatures of 23 degrees, going to a high of 36. The precipitation is expected to move to rainfall as temperatures rise to above freezing in the evening, according to the Weather Channel’s latest estimates.

“We will see some snow begin somewhere close to midday and that period of snow will last a couple of hours. Then it’s possible we see a break in the afternoon and then it will continue intermittently through the evening.” AccuWeather meteorologist Adam Douty told The Post, adding that driving conditions could rapidly deteriorate once things get going.

“As soon as the snow comes in, if surfaces are untreated it will start sticking pretty quickly on roadways. As soon as you start seeing snow, the roads may deteriorate pretty quickly,” he said. ““Since it was so cold last night, it may come in and start sticking right away.”

New York state, New Jersey, Philadelphia and Washington, D.C., can also expect to be affected. Parts of northern Pennsylvania, western New York and New England will receive up to a foot of snow, according to AccuWeather.

The nasty conditions are moving eastward from the Midwest and northern plains which have been pounded by similarly severe weather in recent days according to the weather channel. Parts of Illinois, Michigan and Ohio were blasted with snow, with 5.5 inches in Toledo, Ohio. A 2.5-inch blanket of snow covered Cleveland in just an hour.