December through April, referred to as the dry season, receives just shy of 25 percent of the annual rainfall, usually ahead of cold fronts. June through October is considered the wet season, receiving approximately 65 percent of the yearly total in showers and thunderstorms.

Key West's rainy season traditionally spans from June through October, coinciding almost exactly with the Atlantic hurricane season. During these months, the weather pattern typically follows a predictable tropical cycle: mornings are often bright and humid, followed by intense, short-lived thunderstorms in the mid-to-late afternoon. These "tropical downpours" can be incredibly heavy, sometimes flooding streets for a short time, but they often clear up within an hour, leaving behind beautiful sunsets. September is statistically the wettest month, seeing an average of over 6 inches of rainfall. While the rain might seem like a deterrent, it often provides a much-needed break from the sweltering Florida heat. For travelers, the rainy season means higher humidity levels (often 75% or higher) and the need for flexible plans. However, since the rain is usually brief, you can still enjoy most outdoor activities. The only major risk during this season is the potential for tropical storms or hurricanes, which can lead to mandatory evacuations of the Florida Keys, so purchasing "cancel-for-any-reason" travel insurance is highly recommended for trips during this window.