Inclement (“of the elements or weather: physically severe”) spiked in lookups on February 9th, 2017. This is something that appears to happen every year, when two things happen: a heartless weather system shows us that the elements do not much care about whether a snow day is inconvenient for you, and everyone who looked up inclement the year before has forgotten what it is.
This word is related to the name that has been borne by 14 Popes over the centuries, Clement (which means “mild” in Latin). By attaching the prefix in- to the word clement it fashioned a word with the meaning of “lacking mildness; unmerciful.” This meaning (which in much of the word’s early use was applied to people, rather than weather) is vividly illustrated in our earliest citation for the word, from William Est’s 1613 work The Triall of True Teares.
God vtterly reiected them, they finde now the heauens inclement towards them, God to neglect them, and whither soeuer they turne themselues, they are exposed to the hissings, reproaches, and iniuries of all Nations.
—WIlliam Est, The Triall of True Teares, 1613
And in case you were wondering: yes, clement can be applied to weather, with the meaning of “mild.”