1938, on model of earlier summerize (1935); from winter (n.) + -ize. Related: Winterized; winterizing.
Entries linking to winterize
winter n.
Old English winter (plural wintru), "the fourth and coldest season of the year, winter," from Proto-Germanic *wintruz "winter" (source also of Old Frisian, Dutch winter, Old Saxon, Old High German wintar, German winter, Danish and Swedish vinter, Gothic wintrus, Old Norse vetr "winter"), probably literally "the wet season," from PIE *wend-, nasalized form of root *wed- (1) "water; wet"). On another old guess, cognate with Gaulish vindo-, Old Irish find "white." The usual PIE word is *gheim-.
As an adjective in Old English. The Anglo-Saxons counted years in "winters," as in Old English ænetre "one-year-old;" and wintercearig, which might mean either "winter-sad" or "sad with years." Old Norse Vetrardag, first day of winter, was the Saturday that fell between Oct. 10 and 16.
-ize
word-forming element used to make verbs, Middle English -isen, from Old French -iser/-izer, from Late Latin -izare, from Greek -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached.
The variation of -ize and -ise began in Old French and Middle English, perhaps aided by a few words (such as surprise, see below) where the ending is French or Latin, not Greek. With the classical revival, English partially reverted to the correct Greek -z- spelling from late 16c. But the 1694 edition of the authoritative French Academy dictionary standardized the spellings as -s-, which influenced English.
In Britain, despite the opposition to it (at least formerly) of OED, Encyclopaedia Britannica, the Times of London, and Fowler, -ise remains dominant. Fowler thinks this is to avoid the difficulty of remembering the short list of common words not from Greek which must be spelled with an -s- (such as advertise, devise, surprise). American English has always favored -ize. The spelling variation involves about 200 English verbs.