Florida Keys Weather in September
Thinking of visiting Florida Keys in September? Expect very high temperatures reaching 31°C (88°F) during the day, dropping to 26°C (79°F) at night, and be prepared for the wettest month of the year.
Rainfall in Florida Keys in September
Prepare for the heaviest rain of the year this month, which often comes in heavy showers. A poncho is a smart choice to stay dry. Historically, September sees about 22 days of rain, with a monthly average of 191 mm (7.5 in). Wet weather is a regular and significant part of this month. Frequent days of rain combined with high totals means proper waterproofs are worth packing.
Temperature in Florida Keys in September
In September, Florida Keys gets very high temperatures, with highs of 31°C (88°F). Nights cool to around 26°C (79°F). It's usually most comfortable outside during the morning and later in the day. With overnight lows of 26°C (79°F), evenings and nights remain warm. Light clothing and an open window or fan can help you sleep comfortably.
Sunshine in Florida Keys in September
Enjoy a sunny month with about 270 hours of sunshine, the clear skies make Florida Keys even more beautiful.September in Florida Keys can still be great, but if you prefer pleasant temperatures along with dry and sunny conditions, our weather planner can help you explore other options in the world.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Florida Keys's climate page.
Florida Keys Temperature in September
Min Temperature
26°C (79°F)
Max Temperature
31°C (88°F)
Chance of Rain
72%
Precipitation
191 mm (7.5 in)
Rainy days
22 days
Humidity
76%
Sunshine
270 hours
Percentage Sunshine
73%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Florida Keys typically stay consistent throughout September, with daily highs averaging around 31°C (88°F). Nights are warm, with lows around 25°C (77°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Florida Keys in September
Browse day-by-day weather records for Florida Keys spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Florida Keys historical weather extremes in September
Based on 49 years of weather observations (1976-2025), these are the most extreme conditions recorded in Florida Keys.
- The hottest September day on record in Florida Keys reached 35°C (95°F) (September 17, 1995).
- On September 30, 1984, Florida Keys saw its coldest September day with temperatures maxing out at 24°C (75°F).
- Nighttime temperatures dropped to 19°C (66°F) on September 10, 1980, marking the coldest September night on record.
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
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What to Wear in Florida Keys in September
Warm but pleasant conditions in Florida Keys in September. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. It's going to pour! Pack a good poncho and prepare for very wet conditions. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.What To Do in Florida Keys in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Florida Keys's climate page.
Temperature Rainfall Sunshine Humidity
See the full Florida Keys climate overview or explore weather in the United States of America.
