The Big Apple turned into the Big Orange.

New Yorkers may have thought the apocalypse was upon them early Wednesday when they awoke to an eerie, tangerine-colored sky.

“NYC sky today an unreal glow of pink and orange during sunrise,” Matt McDermott tweeted along with images of Gotham immersed in the ethereal light.

Some thought the strange sky was downright biblical.

“Finally Christ is coming back to save us from this misery,” tweeted Mister Resister, who figured the glow was a sure sign of “Judgement Day.”

But the answer to the mystery was more down to Earth — a rare confluence of early-morning sunlight, humidity and haze, according to an AccuWeather meteorologist.

“A rain system from the west arrived as the sunlight peeked through the clouds,” Paul Walker told The Post. “It was very humid as the light reflected through water droplets, haze and dust, giving the sky that color.”

The sun shone from a low angle through the thick atmosphere and its rays with shorter wavelengths, such as the normal blue, scattered away, producing the unusual hue.