Key West Weather in September

Thinking of visiting Key West in September? Expect very high temperatures reaching 32°C (90°F) during the day, dropping to 26°C (79°F) at night, and be prepared for the wettest month of the year.

Rainfall in Key West in September

Expect the heaviest rain of the year this month, often arriving in intense bursts. A poncho is essential for keeping dry. On average, there are about 23 days with rain during this month, averaging 163 mm (6.4 in). Rain falls regularly this month and can be quite heavy when it does. Showers can be substantial, so waterproof gear is a good idea.

Temperature in Key West in September

If you're visiting Key West in September, expect highs of 32°C (90°F) and overnight lows around 26°C (79°F). Sunshine and humidity can make it feel even warmer than the raw temperature suggests. At 26°C (79°F) overnight, the heat doesn't let up much after dark. If you're staying somewhere without air conditioning, a cold shower before bed and keeping the air moving can help.

Sunshine in Key West in September

The city usually sees around 271 hours of sunlight, indicating many sunny days , a great month for sightseeing.

Average water temperature in September

The water is 30°C (86°F), very warm by most standards. Comfortable to swim in, but not particularly refreshing if you're looking to cool off.

September in Key West has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.