Key West is warm year-round, but the best time to visit is between November and April, when humidity drops and temperatures sit comfortably in the mid-20s Celsius (mid-70s Fahrenheit). This is also peak tourist season, so expect higher prices and bigger crowds, especially around the holidays and during Fantasy Fest in late October. Summer is hot, humid, and prone to afternoon thunderstorms, but it is also significantly cheaper and less crowded. Hurricane season officially runs from June through November, with September and October carrying the highest risk. The water is swimmable all year.