Key West water temperature
The sea off Key West is warmest in August, around 86°F (30°C), and coolest in February, around 71°F (22°C).
Photo: Julian Lupyan, CC0
Sea temperature by month
| Month | Sea | Feels | Air high |
|---|---|---|---|
| January | 71°F (22°C) | Refreshing | 76°F |
| February | 71°F (22°C) | Refreshing | 77°F |
| March | 73°F (23°C) | Refreshing | 80°F |
| April | 77°F (25°C) | Pleasant | 83°F |
| May | 80°F (27°C) | Warm | 86°F |
| June | 84°F (29°C) | Bath-warm | 89°F |
| July | 85°F (30°C) | Bath-warm | 90°F |
| August | 86°F (30°C) | Bath-warm | 91°F |
| September | 85°F (30°C) | Bath-warm | 89°F |
| October | 83°F (28°C) | Bath-warm | 86°F |
| November | 77°F (25°C) | Warm | 81°F |
| December | 74°F (23°C) | Pleasant | 78°F |
Average sea-surface temperature just offshore, 1991–2020. Water in shallow bays runs a little warmer on sunny afternoons.
On the water in Key West
Questions
When is the water warmest in Key West?
August, at about 86°F (30°C).
Can you swim in Key West all year?
The water is comfortably warm (73°F/23°C or more) in April through December. Outside those months most people want a wetsuit for long swims.
Do I need a wetsuit to snorkel in Key West?
In February, at 71°F, a 3 mm wetsuit makes a long snorkel much more comfortable. Many tours include or rent one.
