Weather and seasons in Italian

Two thirds of the way down sits sereno, the same Latin word as « serene » doing a different job. In Italian the first thing sereno describes is the sky: il cielo è sereno, una giornata serena, and as a noun il sereno is fair weather itself — dopo la pioggia torna il sereno. Serenus meant exactly that, clear and fair, said of the weather long before it was said of anybody. English borrowed the word and then moved it indoors. « Serene » now belongs to people and to states of mind: a serene smile, serene confidence, « serenity », and « Her Serene Highness », which keeps the calm without a cloud in sight. No forecast uses it, and nobody looking out of a window does either; the everyday words are « clear », « bright » and « cloudless ». The overlap has not vanished, because sereno can also describe a calm person, but the traffic runs one way only. The neatest proof is the idiom: what English calls « a bolt from the blue » is un fulmine a ciel sereno, one language naming the colour of the sky and the other its clearness.