Water temperature in Key West (FL) in December
Is it warm enough to swim in Key West in December? Average water temperature in Key West in December is 77.2°F and therefore suitable for comfortable swimming. The warmest sea in Key West in December is 81°F, and the coldest is 71.4°F. Average high air temperature in Key West in December is 76°F, and average low temperature is 67°F. To find out the sea temperature today and in the coming days, go to Current sea temperature in Key West
Changes water temperature in Key West in December 2025, 2024
To get an accurate forecast for the water temperature in Key West for any chosen month, compare two years within a 10 year range using the chart below. In addition to the sea water temperature in Key West, the selected years in the table also show the values of the maximum and minimum temperatures on each of the days of December.
You can choose any other years:
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| December 1 | 78.8°F | 78.1°F | 75.9°F | 81°F |
| December 2 | 78.4°F | 78.4°F | 75.7°F | 80.6°F |
| December 3 | 78.1°F | 77.5°F | 75.9°F | 80.6°F |
| December 4 | 79°F | 77°F | 75°F | 80.1°F |
| December 5 | 79.9°F | 77°F | 75.9°F | 80.1°F |
| December 6 | 79.7°F | 78.1°F | 75.4°F | 79.9°F |
| December 7 | 79.3°F | 77°F | 74.8°F | 79.9°F |
| December 8 | 80.2°F | 76.5°F | 74.8°F | 80.2°F |
| December 9 | 79.5°F | 77.2°F | 74.7°F | 79.9°F |
| December 10 | 77.2°F | 76.6°F | 73.8°F | 79.5°F |
| December 11 | 78.3°F | 76.8°F | 74.3°F | 79.3°F |
| December 12 | 78.4°F | 75.4°F | 73.8°F | 79.3°F |
| December 13 | 78.6°F | 75.4°F | 73.4°F | 79.9°F |
| December 14 | 77.2°F | 75.6°F | 73.4°F | 79.2°F |
| December 15 | 76.5°F | 73.9°F | 79°F |
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| December 16 | 76.5°F | 73.4°F | 79.3°F | |
| December 17 | 76.8°F | 72.5°F | 79.2°F | |
| December 18 | 77.2°F | 72.3°F | 79.2°F | |
| December 19 | 76.3°F | 72.9°F | 78.8°F | |
| December 20 | 76.8°F | 72.9°F | 78.8°F | |
| December 21 | 76.6°F | 73°F | 79.2°F | |
| December 22 | 75.9°F | 73°F | 78.6°F | |
| December 23 | 75.6°F | 72.5°F | 79°F | |
| December 24 | 74.5°F | 72.3°F | 78.8°F | |
| December 25 | 74.7°F | 72.3°F | 78.3°F | |
| December 26 | 75.2°F | 72.1°F | 77.9°F | |
| December 27 | 75.6°F | 71.6°F | 78.6°F | |
| December 28 | 76.1°F | 71.8°F | 79°F | |
| December 29 | 75.9°F | 71.6°F | 79°F | |
| December 30 | 77.7°F | 71.6°F | 79°F | |
| December 31 | 78.4°F | 71.4°F | 79°F |
Average water temperature in Key West in December over a decade
| 2015 | 2016 | 2017 | 2018 | 2019 |
| 78.6°F | 78.4°F | 77.4°F | 77°F | 77.7°F |
| 2020 | 2021 | 2022 | 2023 | 2024 |
| 77°F | 78.4°F | 78.4°F | 77.7°F | 76.5°F |
Key West sea state in December
Chart comparing the height of waves in Key West in December over the past years. The red line indicates the height of the waves when swimming in the sea is prohibited. To view the current sea conditions, click on the graph.
Weather and climate in Key West in December
This data display average monthly climate indicators in Key West in December based on our historical weather readings over a period of ten years. In addition to temperature, we include data on the number of rainy and sunny days so you can have all the information about your destination before your trip
- Average HIGH temperature76°F
- Average LOW temperature67°F
- Average humidity
76 - Average rainfall days6 days
- Average rainfall46mm/1.8''
- Average daylight11h
- Average sunshine7.6h
- Average UV index6
Key West water temperature during other months:
You can also view information about water temperature for other months by clicking on the month button below
