The warmest ocean waters anywhere on the United States mainland are found in the Florida Keys in winter, with sea surface temperatures averaging in the 75 to 77 °F range in December through February.
With the exception of a few other locations in the Florida Keys, Key West is the only ___location in the mainland U.S. known to never have had a frost or freeze{{spaced ndash}}the lowest temperature on record was {{convert|41|°F}} on January 12, 1886 and January 13, 1981. Prevailing easterly [[tradewinds]] and sea breezes suppress the usual summertime heating, with temperatures rarely reaching {{convert|95|°F|0}}. There are 55 days per year with {{convert|90|°F|0}} or greater highs,<ref name = NOAA /> with the average window for such readings June 10 thru September 22, shorter than almost the entire [[Southeastern United States|southeastern U.S.]] However, low temperatures often remain above {{convert|80|°F|0}}. The all-time record high temperature is {{convert|97|°F|0}} on August 29, 1956 and July 19, 1880.<ref name = NOAA/>
Key West falls under the [[USDA]] 11b Plant [[Hardiness zone]].<ref>|source 1 = <USDA.gov= >{{cite web
