Red sky at night, sailor’s delight.

Red sky at morning, sailor’s warning.

At our house, we’ve added a half-serious, half-ridiculous line to the saying: Yellow sky, prepare to die. Pretty extreme, yes. It comes from my growing up in tornado-prone landscapes. The pre-tornado skies usually progressed from rainy, to cloudy and still, to yellow, and then tornadoes. I don’t know if this is true everywhere, and so many tornadoes come at night, who knows what the sky looks like. But the pronouncement is...