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

86.8

°F

September 24, 16:35

Trend:

stable

Yesterday:

86.7°F

Tomorrow:

86.7°F

Sunrise:

07:16

Sunset:

19:22

Day Length:

12 h. 6 min.

Key West in September

Minimum:

71.4°F

Average:

73.9°F

Maximum:

76.2°F

Sea water temperature in Key West today

As of now, in Key West, the water temperature is 86.8°F. Swimming in water of this temperature is considered highly warm and would be enjoyable for everyone. At this temperature, you can comfortably engage in water-based activities for extended periods without experiencing discomfort. Today's reading is 0.6°F higher than the average recorded on this particular day in recent years. The sea temperature remains approximately unchanged from yesterday. 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 also falls within the range of the average temperature recorded for this date, suggesting a consistent weather trend. The maximum temperature recorded for this date was 88.1°F on 2024, while the historical minimum was 83.5°F on 2019.

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 86.3°F, the minimum temperature may reach 85.6°F, and the maximum might stay at 86.7°F.

Daily water temperature in Key West

Date Current Year

actual* / forecast**

last year 10 years average
Sep 10 89.0°F 86.7°F 86.9°F
Sep 11 87.7°F 86.6°F 86.6°F
Sep 12 88.4°F 87.2°F 86.8°F
Sep 13 88.3°F 86.8°F 86.5°F
Sep 14 88.5°F 86.9°F 86.6°F
Sep 15 88.6°F 86.9°F 86.6°F
Sep 16 88.6°F 87.7°F 86.9°F
Sep 17 88.3°F 87.2°F 86.7°F
Sep 18 87.0°F 86.8°F 86.6°F
Sep 19 87.5°F 86.5°F 86.6°F
Sep 20 87.2°F 86.0°F 86.5°F
Sep 21 86.5°F 86.0°F 86.5°F
Sep 22 86.9°F 85.7°F 86.5°F
Sep 23 86.7°F 85.7°F 86.3°F
Sep 24 86.8°F 86.1°F 86.2°F
Sep 25 86.7°F 86.6°F 86.0°F
Sep 26 86.6°F 86.0°F 86.0°F
Sep 27 86.5°F 87.0°F 85.9°F
Sep 28 86.3°F 87.5°F 85.7°F
Sep 29 86.3°F 87.4°F 85.7°F
Sep 30 86.1°F 86.8°F 85.5°F
Oct 1 85.6°F 86.2°F 85.0°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 332 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 February 7, 2026, dipping to 64.1°F. The average readings by season are 74.0°F in Winter, 79.1°F in Spring, 86.6°F in Summer, and 82.9°F in Autumn.