Measurements:
°C
°F
Key West
90°F
W 9 mph
Feels like: 100°F
Precip: 5%
World Resorts USA Key West Weather

Key West Sea Water Temperature

Current Sea Water Temperature:
+95.0°F
Maximum Sea Water Temperature in August: 96.0°F
Minimum Sea Water Temperature in August: 87.2°F
Average water temperature in August: 91.3°F

Sea Water Temperature for the Last 10 Days:

August 25 95.0°F August 20 93.2°F
August 24 93.8°F August 19 93.4°F
August 23 94.4°F August 18 91.8°F
August 22 94.6°F August 17 93.2°F
August 21 93.4°F August 16 93.2°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

Select Year: 2026 2025 2024

The average sea surface temperature in August 2026 for Key West was 92.9°F. The maximum and minimum values were 91.2°F and 95.0°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Key West was 92.8°F. The maximum and minimum values were 91.6°F and 94.4°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

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.

Best Time to Visit Key West
The most sunny months:
May 17 days
March 16 days
April 16 days
The most warm months:
August 91.6 °F
July 91.0 °F
September 89.7 °F
Warmest sea temperature:
August 91.4 °F
July 90.8 °F
September 90.1 °F
The most cold months:
January 74.4 °F
February 76.3 °F
December 78.2 °F
The most rainy months:
June 7 days
August 7 days
September 6 days
The most windy months:
November 14 mph
December 14 mph
January 14 mph

Key West on the Weather Map

USA Resorts:
NAME
Boston +80
Chicago +82
Hawaii +84
Houston +108
Las Vegas +116
Los Angeles +96
Maui +70
Miami +92
Myrtle Beach +84
New York +82
San Diego +80
San Francisco +64
Santa Monica +86
Sarasota +92
Washington +84
24 Hours Weather Forecast
Key West
Local time: 17:18
25 aug, tuesday
1800 90°F
W
9 mph
2100 90°F
W
13 mph
26 aug, wednesday
0000 90°F
NW
15 mph
0300 90°F
NW
16 mph
0600 90°F
NW
13 mph
0900 90°F
NW
12 mph
1200 90°F
NW
14 mph
1500 90°F
W
11 mph