Key West in September
Find out everything about the water temperature in Key West in September. Average, minimum and maximum recorded temperatures as well as daily temperature in September for the last two years. Compare the current month's sea temperature data with other months of the year.
Water temperature in September
Minimum:
82.8 °F
Average:
86.2 °F
Maximum:
89.6 °F
Sea water temperature in Key West in September
In the city of Key West, the month of September is a great time for swimming. The minimum recorded temperature during this month was 82.8°F on September 25, 2019, with an average temperature being 86.2°F and a maximum temperature reaching 89.6°F on September 16, 2024.
| Date | 10 years average | 2024 | 2023 |
|---|---|---|---|
| Sep 1 | 86.5°F | 86.5°F | 86.6°F |
| Sep 2 | 86.4°F | 86.3°F | 87.0°F |
| Sep 3 | 86.4°F | 86.1°F | 86.5°F |
| Sep 4 | 86.5°F | 86.7°F | 86.7°F |
| Sep 5 | 86.4°F | 87.2°F | 85.6°F |
| Sep 6 | 86.5°F | 87.3°F | 86.0°F |
| Sep 7 | 86.4°F | 87.4°F | 85.8°F |
| Sep 8 | 86.6°F | 88.0°F | 86.3°F |
| Sep 9 | 86.6°F | 87.6°F | 86.1°F |
| Sep 10 | 86.6°F | 87.3°F | 87.2°F |
| Sep 11 | 86.4°F | 88.1°F | 87.5°F |
| Sep 12 | 86.5°F | 89.0°F | 88.0°F |
| Sep 13 | 86.3°F | 88.3°F | 87.6°F |
| Sep 14 | 86.5°F | 88.4°F | 88.6°F |
| Sep 15 | 86.2°F | 88.8°F | 88.2°F |
| Sep 16 | 86.4°F | 89.6°F | 88.6°F |
| Sep 17 | 86.4°F | 89.6°F | 88.0°F |
| Sep 18 | 86.4°F | 88.5°F | 88.8°F |
| Sep 19 | 86.4°F | 88.1°F | 88.5°F |
| Sep 20 | 86.4°F | 87.8°F | 88.6°F |
| Sep 21 | 86.4°F | 87.7°F | 88.2°F |
| Sep 22 | 86.4°F | 88.3°F | 88.1°F |
| Sep 23 | 86.2°F | 88.8°F | 87.9°F |
| Sep 24 | 86.1°F | 88.1°F | 87.9°F |
| Sep 25 | 85.8°F | 87.2°F | 87.7°F |
| Sep 26 | 85.8°F | 85.9°F | 86.9°F |
| Sep 27 | 85.6°F | 85.3°F | 86.8°F |
| Sep 28 | 85.4°F | 83.9°F | 86.5°F |
| Sep 29 | 85.4°F | 85.3°F | 85.7°F |
| Sep 30 | 85.2°F | 85.7°F | 86.6°F |
In Key West, the water temperature is comfortable for swimming all year round.
The warmest water in Key West was recorded on August 12, 2023, reaching a 91.4°F. While the coldest temperature occurred on February 4, 2021, dipping to 67.5°F. The average readings by season are 74.4°F in Winter, 79.0°F in Spring, 86.3°F in Summer, and 82.9°F in Autumn.
September's average temperature is a slight drop from August's average of 87.2°F. In October, the temperature is expected to decrease further, potentially averaging around 83.2°F.