Current Sea Water Temperature:
+76.8°F
| Maximum Sea Water Temperature in December: | 84.0°F |
| Minimum Sea Water Temperature in December: | 72.2°F |
| Average water temperature in December: | 78.6°F |
| detailed information | |
Sea Water Temperature for the Last 10 Days:
| December 18 | 76.8°F | December 13 | 78.6°F |
| December 17 | 76.8°F | December 12 | 79.4°F |
| December 16 | 78.0°F | December 11 | 79.0°F |
| December 15 | 78.4°F | December 10 | 81.8°F |
| December 14 | 79.4°F | December 09 | 82.6°F |
When is the Warmest Sea for Key West?
According to our data for the last three years for Key West the highest average sea water temperature was in August, July and September.
Average Water Temperature by Month, °F
Sea Water Temperature in August
The average sea surface temperature in August 2025 for Key West was 93.1°F. The maximum and minimum values were 91.0°F and 95.2°F respectively.
Sea Water Temperature in July
The average sea surface temperature in July 2025 for Key West was 90.8°F. The maximum and minimum values were 89.0°F and 92.2°F respectively.
Sea Water Temperature in September
The average sea surface temperature in September 2025 for Key West was 91.0°F. The maximum and minimum values were 89.2°F and 93.6°F respectively.
USA Resorts:
NAME
F°
| Chicago |  |
+38 |
| Hawaii |  |
+76 |
| Honolulu | |
+76 |
| Houston |  |
+64 |
| Las Vegas | |
+50 |
| Los Angeles | |
+54 |
| Maui |  |
+72 |
| Miami | |
+72 |
| Miami Beach | |
+78 |
| New York | |
+30 |
| San Diego | |
+52 |
| San Francisco | |
+50 |
| Sarasota | |
+64 |
| Tampa | |
+62 |
| Washington | |
+30 |
Countries:
NAME
POPULARITY
24 Hours Weather Forecast
Key West
Local time: 04:13
18 dec, thursday
| 0600 |  |
76°F | W 18 mph |
| 0900 |  |
78°F | W 17 mph |
| 1200 | |
78°F | W 17 mph |
| 1500 |  |
78°F | NW 14 mph |
| 1800 |  |
78°F | NW 11 mph |
| 2100 | |
78°F | W 10 mph |
19 dec, friday
| 0000 | |
78°F | NW 8 mph |
| 0300 | |
78°F | N 6 mph |