Key West Weather
SPOILER ALERT: The weather in Key West is awesome. Warmed by sun and sea, cooled by wind and rain, Key West weather is always great. Let Cool Key West help you plan a frost-free vacation in tropical Key West.
The Florida Keys form a barrier that divides the Gulf of Mexico from the Atlantic Ocean, with the waters of the two merging in the Straits of Florida between Key West and Cuba. The uniformly great Key West weather arises from this location between the two differing bodies of water, as well as from the island’s tropical latitude. The Gulf is much warmer and calmer than the Atlantic, and has a major current that drives heated water along both sides of the Keys.
The Gulf Loop Current is a primary factor in Key West weather. The Loop is born of water pushed by the Earth’s rotation from the Atlantic onto the coast line of Central America and up into the western Gulf, where it runs up the coast of Mexico, across the Southern seaboard of the U.S., and down the western Florida shoreline. The moving water picks up heat along the way, and as it exits the Gulf running east through the Straits of Florida, it is very warm. With surface temperatures averaging 75 to 77°F from December through February, it is the warmest ocean water on the United States mainland.This warm water keeps the Key West weather very mild and stable, with only about a 15°F variation in mean monthly temperatures throughout the year.
The Keys are the only U.S. mainland location where frost or freezing temperatures have never been recorded. The lowest temperature recorded in Key West was 41°F on January 12, 1886, and again on January 13, 1981. Summer temperatures are moderate as well, mellowed by easterly trade winds and local sea breezes drawn off the cool waters of the Atlantic. While Key West weather in the summer may certainly feel hot, the record high summer temperature mark is only 97°F.
Although it might be imagined that a tropical location like Key West is rainy, the island actually has a tropical savannah climate similar to the Caribbean islands rather than a rainforest or monsoon climate. The island has a pronounced dry season and gets only 39 inches of rain per year, a little more than the U.S. average of 37 inches and much less than the 50 to 60 inch average common to the rest of Florida.
The weather in Key West is characterized mainly by the wet and dry seasons. In the months of November through April, the island receives many of its average 260 sunny days per year and about 25 percent of the annual rainfall, usually in advance of cold fronts that move in from the northeast in waves. The wet season runs from May through October, with numerous showers and thunderstorms bringing in about 53 percent of the yearly precipitation, often as early morning rains that are followed by intensely hot afternoon sun.
Unlike mainland Florida and the Gulf Coast, Key West is not often the direct target of hurricanes. The average time between direct hits is 5.88 years, with a 21 year gap between hits occurring from 1966-1987. However, when close brushes are factored in, the island receives some storm effects every 2.71 years. Most tropical storms tracking through the Gulf tend to move north of the Keys, but the island can be affected by the wind and rainfall of storm systems that are hundreds of miles away. Due to the low-lying nature of the Keys, they are vulnerable to the storm surges and rain-fall induced flooding common to tropical storms.