Key West in september: average Weather, Temperature and Climate
Weather in Key West in september 2025
The weather in Key West in september comes from statistical datas on the past years. You can view the weather statistics the entire month, but also by clicking on the tabs for the beginning, the middle and the end of the month.
Average weather throughout september
tolerable weather UV index: 7
Weather at 6am
85°F
Moderate rain at times
32% of time
27%
21%
16%
Weather at 12pm
85°F
Clear/Sunny
29% of time
24%
23%
21%
Weather at 6pm
85°F
Clear/Sunny
42% of time
25%
20%
13%
Weather at 3am
85°F
36%
27%
24%
12%
Evolution of daily average temperature and precipitation in Key West in september
These charts show the evolution of average minimum/maximum temperatures as well as average daily precipitation volume in Key West in september.
The climate of Key West in september is tolerable
The weather in september in Key West is wet (with 11.3in of rainfall over 16 days). The situation is deteriorating compared to the previous month since in august there is an average of 10.2in of rainfall over 15 days.
The climate quite pleasant around this city september. Temperatures are up to 86°F. The minimum is 85°F. Thus, the mean temperature average in september in Key West is 85°F. Note that these seasonal averages are in contrast with those observed in Key West in the month of september with a maximum record of 88°F in 2017 and a minimum record of 76°F in 2020. You can plan to have about 8 days with temperatures over 86°F, or 27 of the month.
In september in Key West, the days on average last 12:17. Sunrise is at 06:13 and sets at 18:30.
With a correct weather, this month is okay (but not the best) to go in that area in United States.
September: another location in Florida?
If you want to go to Florida in september, there are destinations with better weather than Key West:
In september, Everglades National Park, Apalachicola, Cedar Key, Falling Waters State Park, Fort Walton Beach and Gainesville have good weather.
Seasonal average climate and temperature of Key West in september
Check below seasonal norms These statistics are compiled from the weather statements of the last years of the month of september.
| September | |||||
| Outside temperature | |||||
| Average temperature | 85°F | ||||
| Highest temperature | 86°F | ||||
| Lowest temperature | 85°F | ||||
| Highest record temperature | 88°F (2017) | ||||
| Lowest record temperature | 76°F (2020) | ||||
| Number of days at +86°F | 8 day(s) (27%) | ||||
| Number of days at +65°F | 30 day(s) (100%) | ||||
| Sea temperature | |||||
| Average sea temperature | 86°F | ||||
| Lowest sea temperature | 84°F | ||||
| Highest sea temperature | 88°F | ||||
| Wind | |||||
| Wind speed | 19km/h | ||||
| Wind temperature | 85°F | ||||
| Precipitation (rainfall) | |||||
| Rainfall | 11.3in | ||||
| Number of days with rainfall | 16 day(s) (52%) | ||||
| Record daily rainfall | 8.6in (2017) | ||||
| Other climate data | |||||
| Humidity | 76% | ||||
| Visibility | 9.19km | ||||
| Cloud cover | 29% | ||||
| UV index | 7 | ||||
| Daily sunshine hours | 12 | ||||
| Sunrise and sunset | |||||
| Time of sunrise | 06:13 | ||||
| Time of sunset | 18:30 | ||||
| Length of day | 12:17 | ||||
| Our opinion about the weather in september | |||||
| Our opinion at whereandwhen.net | tolerable | ||||
How was the weather last september?
Here is the day by day recorded weather in Key West in september 2024:
83°F to 85°F
83°F to 85°F
85°F to 85°F
85°F to 85°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
86°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
85°F to 86°F
83°F to 86°F
85°F to 85°F
83°F to 85°F
85°F to 85°F
83°F to 86°F
85°F to 86°F
85°F to 85°F
85°F to 86°F
85°F to 85°F
83°F to 86°F
81°F to 83°F
81°F to 83°F
Map: other cities in Florida in september
Cities near Key West:
| Big Pine Key in september | tolerable weather |
| Dry Tortugas National Park in september | tolerable weather |
| Everglades National Park in september | good weather |
| Islamorada in september | tolerable weather |
| Key Largo in september | tolerable weather |
| Marco Island in september | tolerable weather |
| Naples in september | tolerable weather |
| Big Cypress National Preserve in september | tolerable weather |
| Biscayne National Park in september | tolerable weather |
| Miami in september | tolerable weather |
| Sanibel Island in september | tolerable weather |
| Captiva Island in september | tolerable weather |
Click over cities on the map for information about the weather in september.
Key West
perfect weather
good
tolerable
bad
very bad
Weather data for Key West in september:
Weather data for Key West for september are derived from an average of the weather forecast since 2009 in Key West. There is a margin of error and these forecasts are to be considered as general information only. The weather in Key West can vary slightly from year to year, but this data should limit surprises. So you can pack your bags or check for the best time in year to go to Key West.