Of course, you can! Swimming in Key West in December will be a pleasant experience.
The waters during this month are warm, and the temperatures remain between 75 degrees and 78 degrees Fahrenheit. However, be on your guard as the weather is unpredictable as storms may pass through. Also, during the winter months, Key West is at its highest in terms of price and busyness.
Even though December throughout the United States demarks the winter season, the weather in Key West during this time is warm and mild. This phenomenon makes it ideal for those seeking to escape the chill of winter across the continental states.
December also falls just outside the hurricane or rainy season, but there is that likelihood of late storms and infrequent rains. However, the weather is usually very reliable, making it an excellent month for water activities such as swimming.
In December, the waters of Key West tend to have excellent visibility as well. The residents of Key West take full advantage of the reduced number of swimmers, so the waters will not be empty. Snorkeling, swimming, and diving are local favorites.
Key West experiences a tropical climate all year round, with temperatures fluctuating by only a few degrees between the coldest and hottest months [source].
In Florida: Is swimming allowed in key west in January?
Best Time For Swimming
If you prefer to stay clear of the crowds in general, the ideal time for swimming is between June and August, as the rest of the country enjoys the summer weather. So fewer people are flocking to the Keys. However, this period in Key West falls within the wet season and hurricane season, so the possibility of storms increases.
If the water temperature is your concern, then between January and May would be the best time for swimming. The temperature consistently increases each month, as January is the end of the winter season for Key West. Another advantage is that the winter crowd starts to taper off. Also, the hotel rates and other consumables are more reasonable.