All data are in degrees Fahrenheit

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Water temperature in Key West

Detailed information about the current water temperature in Key West. The trend over the last two weeks, daily averages, and precise forecast of the water temperature changes. Gain a deeper understanding of seasonal dynamics with monthly statistical analyses covering recent years.
Sea temperature in Key West now

74.5

°F

December 19, 08:34

Trend:

stable

Yesterday:

74.2°F

Tomorrow:

74.2°F

Sunrise:

07:06

Sunset:

17:43

Day Length:

10 h. 37 min.

Key West in December

Minimum:

68.5°F

Average:

73.0°F

Maximum:

75.6°F

Sea water temperature in Key West today

As of now, in Key West, the water temperature is 74.5°F. It's safe to say that the water is comfortably warm for various water-related activities. Today's reading is 1.6°F lower than the average recorded on this particular day in recent years. Since yesterday, there was a slight increase in temperature. This indicates a warming trend over the past day. According to the forecast, we expect the temperature to fall a bit.

Recent sea temperature and forecast

Today's water temperature is considerably lower than the average registered over the last two weeks, indicating a slight cooling trend. It is also close to the historical minimum temperature for this date. The maximum temperature recorded for this date was 78.5°F on 2015, while the historical minimum was 74.2°F on 2023.

The water temperature over the last two weeks displayed soome variability. While the two week average stayed close to the historical average, there were some days when the temperature was close to the maximum recorded over the past years. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 73.3°F, the minimum temperature may reach 72.6°F, and the maximum might stay at 74.2°F.

Daily water temperature in Key West

Date Current Year

actual* / forecast**

last year 10 years average
Dec 5 77.2°F 71.6°F 76.8°F
Dec 6 78.6°F 72.8°F 76.8°F
Dec 7 78.5°F 73.9°F 76.9°F
Dec 8 78.4°F 72.1°F 76.6°F
Dec 9 79.4°F 70.7°F 76.4°F
Dec 10 78.7°F 72.6°F 76.4°F
Dec 11 76.1°F 72.4°F 76.1°F
Dec 12 76.5°F 73.5°F 76.3°F
Dec 13 75.7°F 71.7°F 75.9°F
Dec 14 76.4°F 71.0°F 76.0°F
Dec 15 75.6°F 71.3°F 75.9°F
Dec 16 75.2°F 71.6°F 76.0°F
Dec 17 74.2°F 72.4°F 76.1°F
Dec 18 74.2°F 73.5°F 76.0°F
Dec 19 74.5°F 74.2°F 76.1°F
Dec 20 74.2°F 73.5°F 75.8°F
Dec 21 73.6°F 72.8°F 75.2°F
Dec 22 73.5°F 72.1°F 75.1°F
Dec 23 73.2°F 71.0°F 74.8°F
Dec 24 72.9°F 70.9°F 74.4°F
Dec 25 72.8°F 70.3°F 74.4°F
Dec 26 72.6°F 71.0°F 74.2°F

* actual - actual temperature values

** forecast - projected values for the next week

Real-time coastal temperatures could deviate by several degrees from the provided readings. These deviations often become evident following intense rainfall or strong winds.

Our forecasting methodology leverages a mathematical model, that uses current water and weather conditions, historical records, wind intensity and direction.

Sea water temperature in Key West by month

In Key West, almost every month besides January is comfortable for swimming. Which amounts to 333 swimming days.
The warmest water in Key West was recorded on August 12, 2023, reaching a 91.4°F. While the coldest temperature occurred on January 26, 2025, dipping to 66.0°F. The average readings by season are 74.2°F in Winter, 79.1°F in Spring, 86.4°F in Summer, and 82.9°F in Autumn.