Gold Coast
Miami Beach Water Temperature
Government Cut, South Beach, and Biscayne Bay's ocean side.
That is right about average for this time of year, and holding steady over the last two weeks. The September average here is 87°F.
Updated Sunday, September 20 — sea-surface temperature modeled for Miami Beach by Open-Meteo.
Out in the open Gulf, NOAA buoy VAKF1 — 3 miles offshore — is reading 85°F. Deep water offshore runs cooler than the shallows in summer and warmer in winter, so it won't match the beach.
For swimming
Very warm
Bath-warm. Pleasant, though it stops being much relief from the heat of the day.
For fishing
Hot — fish the edges of the day
Early and late is the play. Through the middle of the day fish drop into deeper channels and passes where there's moving water and more oxygen.
The last two weeks
Daily average sea-surface temperature, °F.
Miami Beach water temperature by month
Averaged from 3 years of daily sea-surface temperature (2023–2025). The range column is the coolest and warmest daily average recorded in that month over the period — a guide to how much any given year can differ, not a record high and low.
| Month | Average | Range | Swimming |
|---|---|---|---|
| January | 73°F | 70–77°F | Cool but comfortable |
| February | 75°F | 72–80°F | Warm |
| March | 77°F | 73–82°F | Warm |
| April | 79°F | 75–83°F | Warm |
| May | 84°F | 78–88°F | Very warm |
| June | 86°F | 84–88°F | Very warm |
| July | 89°F | 85–92°F | Bath water |
| August | 89°F | 86–92°F | Bath water |
| Septembernow | 87°F | 84–89°F | Very warm |
| October | 83°F | 80–87°F | Very warm |
| November | 79°F | 76–82°F | Warm |
| December | 76°F | 72–80°F | Warm |
Warmest on average in July at 89°F; coolest in January at 73°F.
The water at Miami Beach
Miami Beach fronts Government Cut, the deep ship channel into Biscayne Bay, and the jetties there are one of the best-known tarpon and snook spots in the country — big fish holding in fast, clear water in the middle of a city. The beach itself gives up snook, jacks, and pompano, and Biscayne Bay behind it holds bonefish and permit on the flats. Blue water is a couple of miles off South Beach.
Government Cut & South Beach
What moves the water temperature here
The Gulf shelf off this coast is shallow, which is why the water swings so much more between summer and winter than open ocean at the same latitude does. Shallow water heats fast and gives that heat up fast: a single strong winter cold front can pull the inshore bays several degrees down in a couple of days, while the beaches a mile offshore barely move. Wind direction matters too — a sustained offshore breeze can pull cooler water up from below and drop the beach temperature noticeably in a morning.
Inshore bays, canals and flats run warmer than the beach through the summer and colder through the winter, for the same reason. The reading above is for the open water at Miami Beach; expect the back bays to be a few degrees either side of it depending on the season.
Common questions
- What is the water temperature at Miami Beach right now?
- The water at Miami Beach is currently about 87°F (31°C). The September average here is 87°F.
- Is the water warm enough to swim at Miami Beach in September?
- September averages 87°F at Miami Beach, which most people would call very warm. Bath-warm. Pleasant, though it stops being much relief from the heat of the day.
- When is the water warmest at Miami Beach?
- July is the warmest month on average at 89°F, and January the coolest at 73°F. 11 months of the year average 75°F or above.
- Why does the water temperature change so quickly here?
- The Gulf shelf off this coast is shallow, so it heats and cools far faster than deep open ocean. A strong winter cold front can pull the inshore water down several degrees in a couple of days, and a sustained offshore wind can drop beach temperatures in a single morning by pulling cooler water up from below.