The temperatures in Key West during September are extremely high, between 28°C and hot as 29°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in Key West. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Key West in September 2025.
If you’re planning to visit Key West in the near future, we highly recommend that you review the 14 day weather forecast for Key West before you arrive.
Temperatures
29° / 28°
Rainy Days
12
Snowy Days
0
Dry Days
18
Rainfall
286
mm
Sun Hours
11.6
Hrs
