United StatesAverage weather for Key West in September
It's hot in September in Key West with an average temperature of 32°C. Temperatures this month range from a low of 31°C to a high of 32°C. At night, you can expect temperatures between 26°C and 29°C.
Start of September
The month of September starts in Key West with hot temps, averaging around 32°C during the day and nights around 28°C. You can expect regular precipitation, but there will also be some sunny days in the early part of the month. Light clothing like shorts or a dress, and a hat and sunglasses are perfect.
Mid September
By mid-September, daytime temps stay steady at around 32°C, with nights around 28°C. During this part of the month, you might see regular precipitation, but there will also be some sunny days. Light clothing like shorts or a dress, and a hat and sunglasses are perfect.
End of September
By the end of September, the average daytime temperature in Key West is around 32°C, while nighttime temps are about 28°C. There’s a significant chance of many days with precipitation. Light clothing like shorts or a dress, and a hat and sunglasses are perfect.
Water temperature
The water temperature at Key West is 31°C this month. It’s really warm, perfect for a swim.
In September, there is an average of 190 mm of precipitation, spread over 12 days. The wind speed is around 3 Bft, mostly coming from the Southeast.
Key West in September |
New York | ||
|---|---|---|---|
 Average temperature |
32°C | 27°C | |
 Max. temperature |
32°C | 31°C | |
| Min. temperature |
31°C | -5°C | |
 Total precipitation |
190 mm | 57 mm | |
| Rainy days |
12 days | 9 days | |
August
UV index
The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
Is September a good time to visit Key West?
Looking for sun? September isn’t a good month to be in Key West. The temperature is nice, but there’s too much chance of rain.
The hurricane season in Key West runs from June to November.
Temperature records
With 35°C in 2017, Key West reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 27°C in 2014. The extreme nighttime temperatures ranged from a lowest recorded value of 22°C to a highest value of 30°C.
Check out the climate of Key West for all months and discover the best travel time
Daily Temperature in September in Key West
This chart shows the average daily high and low temperatures in September for Key West, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in September in Key West
The chart below shows the average daily precipitation in September for Key West, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 12 days of precipitation in Key West.
Daily UV index in September in Key West
This chart shows the average daily UV index in September in Key West, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Key West over the years
This chart shows the average temperature in September in Key West, measured in degrees Celsius, over the past few years.
Total precipitation in September in Key West over the years
This chart shows the average precipitation in September in Key West, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
Daily weather in September for Key West
Click on any day in September to get detailed info about the usual weather on that day in Key West. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Key West
Have you been to Key West in September?
Share your weather experience in September in Key West.
Average weather in Key West by month
Click on a month below to see detailed weather info for Key West. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
