What is Key West’s Weather In September?

A September Serenade: Weather and Island Adventures in Key West

September in Key West, Florida, ushers in the beginning of the autumn season and offers visitors a tropical paradise characterized by warm weather and a wide range of activities. As the summer begins to wane, Key West remains an inviting destination for those seeking sunshine, water-based adventures, and cultural experiences. In this article, we explore the weather in Key West during September and guide you through the joys of an autumn escape to this island oasis.

Temperature in September

September in Key West features warm and pleasant temperatures. The average high temperature during the day typically ranges from 88°F to 90°F (31°C to 32°C), while the nighttime lows generally stay above 78°F (26°C). These comfortable temperatures create an ideal environment for beach outings, water sports, and outdoor exploration.

Precipitation and Rainfall

September is a transition month in Key West, and it experiences a gradual decrease in rainfall compared to the previous summer months. The island receives an average of about 4 inches (102 mm) of precipitation throughout the month. While there may be occasional rain showers, they are usually short-lived and interspersed with sunny spells.

Sunshine and Daylight

September in Key West still boasts ample sunshine, with around 8 hours of daily sunlight. This extended daylight period ensures you have sufficient time to relish the island’s natural beauty, historical sites, and outdoor activities.

Humidity and Wind

Relative humidity levels in Key West during September tend to remain around 75%. While it can feel somewhat humid, the island continues to enjoy refreshing sea breezes. These breezes make the outdoor environment comfortable and are particularly delightful for water activities like sailing, snorkeling, and beachside strolls.

Water Temperature

The waters surrounding Key West are still warm in September, with an average water temperature of around 86°F (30°C). This inviting water temperature is perfect for swimming, snorkeling, and underwater adventures, offering an excellent opportunity to explore the region’s vibrant marine life and coral reefs.

Activities and Events

September in Key West offers a diverse range of activities and events, ensuring there’s something for every traveler. Here are some recommendations:

  1. Beach Delight: Soak up the sun on Key West’s gorgeous beaches, including Fort Zachary Taylor State Park Beach and Smathers Beach.
  2. Water Adventures: Engage in water activities like snorkeling, diving, kayaking, paddleboarding, and jet skiing in the warm, clear waters.
  3. Historical Exploration: Discover the island’s history at attractions such as the Harry S. Truman Little White House and the Mel Fisher Maritime Museum.
  4. Fishing: Enjoy prime fishing opportunities to catch species like tarpon, mahi-mahi, and wahoo.
  5. Festivals and Events: Partake in cultural events such as the Womenfest Key West and the Key West Brewfest.


September in Key West offers a tropical paradise with warm temperatures, ample sunshine, and a wide array of water-based and cultural experiences. Whether you’re seeking a beach vacation, underwater adventures, or historical exploration, the weather in Key West during September provides the perfect backdrop for an unforgettable autumn getaway. Immerse yourself in the island’s natural beauty and vibrant culture during this transitional month, and create cherished memories in this tropical haven.

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