A whole patch of the sky went green at sunset this afternoon. By the time I stopped driving and found a vantage point it had diminished somewhat but was still visible at the centre of the shot above.
The phenomenon of the green flash refers to the sun going momentarily green at sunset and I guess this related as the sun's refracted light is being projected onto some clouds in addition to the red, orange and yellow light frequencies that are more usual.
In a less analytic sense - it was pretty weird!