Sea temperature and swimming season in Miami
The sea off Miami is comfortable for swimming all year round — it never drops below 24.4°C, and peaks at 30.3°C in August.
Month by month
Sea temperature, the air you climb out into, and the wind that decides how that feels.
| Month | Sea | Air | Wind | Feels | What to wear |
|---|---|---|---|---|---|
| January | 24.6°C | 23.9°C ↓ | 4.1 m/s | Very comfortable | none needed |
| February | 24.4°C | 22.8°C ↓ | 4.2 m/s | Very comfortable | none needed |
| March | 25.3°C | 26.3°C | 3.9 m/s | Very comfortable | none needed |
| April | 26.2°C | 27.1°C | 4.1 m/s | Bath-like | none needed |
| May | 27.7°C | 27.3°C ↓ | 4.7 m/s | Bath-like | none needed |
| June | 28.8°C | 29.7°C | 2.6 m/s | Bath-like | none needed |
| July | 29.9°C | 30.3°C | 2.4 m/s | Bath-like | none needed |
| August | 30.3°C | 29.9°C ↓ | 3.0 m/s | Bath-like | none needed |
| September | 30.0°C | 29.4°C ↓ | 2.6 m/s | Bath-like | none needed |
| October | 28.8°C | 28.8°C | 3.2 m/s | Bath-like | none needed |
| November | 27.3°C | 25.0°C ↓ | 4.6 m/s | Bath-like | none needed |
| December | 26.0°C | 26.1°C | 5.4 m/s | Bath-like | none needed |
Air is the average daily maximum — roughly what you would meet swimming in the middle of the day. An arrow marks months where the air is colder than the sea.
When in the day can you swim?
Daylight and burn risk by month, in America/New_York local time.
| Month | Sunrise | Sunset | Daylight | Peak UV |
|---|---|---|---|---|
| January | 07:09 | 17:51 | 10h 42m | 5.4 |
| February | 06:55 | 18:14 | 11h 18m | 7.3 |
| March | 07:29 | 19:29 | 12h 00m | 9.6 |
| April | 06:57 | 19:43 | 12h 46m | 11.6 |
| May | 06:34 | 19:59 | 13h 24m | 12.5 |
| June | 06:29 | 20:13 | 13h 44m | 12.8 |
| July | 06:39 | 20:14 | 13h 36m | 13.1 |
| August | 06:53 | 19:56 | 13h 03m | 12.8 |
| September | 07:06 | 19:25 | 12h 18m | 11.3 |
| October | 07:19 | 18:53 | 11h 34m | 8.8 |
| November | 06:38 | 17:31 | 10h 53m | 6.2 |
| December | 06:59 | 17:32 | 10h 32m | 5.0 |
Open water burns faster than a beach: the surface reflects sunlight up at you, and sunscreen washes off in the first few minutes. A long swim under a UV index above 6 needs a rash vest more than it needs more cream.
What the bands mean
| From | Description | In practice |
|---|---|---|
| above 26°C | Bath-like | Warm enough that it offers no cooling at all |
| above 22°C | Very comfortable | Swimwear, no time limit for most people |
| above 19°C | Comfortable | Pleasant once you are in; most people swim happily |
| above 16°C | Bracing | Swimmable but short; many prefer a shorty wetsuit |
| above 12°C | Cold | Wetsuit territory. Unprotected swims should be brief |
| below 12°C | Dangerous | Cold shock risk. Specialist gear and supervision |
Do you need a wetsuit in Miami?
No. The sea here never falls below 24.4°C, so there is no month in which neoprene is the thing standing between you and a comfortable swim. A rash vest is worth having, but for the sun on your back rather than for warmth — the surface burns while you swim, and you will not feel it happening.
Other coastal cities in United States
Where these numbers come from, and what they miss
- Open water, not your beach. The measurement is a satellite cell about 28 km across, centred 13.1 km from Miami. Shallow bays and lagoons run warmer; exposed coasts with upwelling run colder, sometimes by several degrees.
- Surface temperature. Below a few metres the sea is often noticeably colder, and in summer a warm surface layer can sit over much colder water.
- A six-year average, not a thirty-year normal. Sea temperature varies little between years, so this is close — but it is not a climate normal, and any individual year will differ.
- Averages hide storms. A monthly mean says nothing about the week a cold current arrives.