Disclaimer: Observation, Forecast, and Warning data are generally available upon request via your local weather office. However, data obtained through a Weather Forecast Office is UNOFFICIAL data and generally not acceptable for legal use. The data posted on this Florida Keys Climatology website is unofficial station data. For official climate records, please visit the National Centers for Environmental Information.
Note on new page layout: The F6 Monthly Climate Data text files for Key West International and Florida Keys Marathon Airports will no longer be produced for this page. The orignal files will continue to be available on the main Climate page for the Florida Keys, under the product name Preliminary Monthly Climate Data (CF6).
Key West is located near the western end of the Florida Keys -- a chain of islands swinging in a southwesterly arc from the southeast coast of the Florida peninsula. Due to the nearness of the Gulf Stream in the Straits of Florida, and the tempering effects of the Gulf of Mexico, Key West has a notably mild, tropical-maritime climate.
Diurnal temperature variations throughout the year range about 10 degrees. Winter cold fronts tend to be modified by the warm water as they move in from the north, keeping monthly average temperatures typically only 15 degrees lower in the winter than during the summer. There is still no record of frost, ice, sleet, or snow in Key West, but ice has been reported in the Upper Keys.
December through April, referred to as the dry season, receives roughly 25 percent of the annual rainfall, usually ahead of cold fronts. June through October is considered the wet season, receiving approximately 60 percent of the yearly total in showers and thunderstorms. Easterly waves during this season occasionally bring excessive rainfall, while infrequent hurricanes may be accompanied by unusually heavy amounts.
Normal Temperature & Precipitation Tables