Month-specific sea-surface temperature · USA
Key Largo Sea Temperature in March
25.2°C
77.4°F
In March, sea-surface temperature near Key Largo has a historical monthly average of 25.2°C. This is not the reading for any particular holiday date.
Across 2022–2025, the lowest and highest yearly March monthly means were 24.2–25.8°C. These are not daily extremes.
Previous month
February · 23.6°C
Change into March: +1.6°C
Next month
April · 26.2°C
Change into next month: +1.0°C
Can you swim or snorkel in Key Largo in March?
At 25.2°C our temperature-only guide describes the water as warm water. Comfort depends on your cold tolerance, immersion time and wind. A historical average cannot determine whether conditions are safe on any given day.
Do you need a wetsuit?
Most people are comfortable in swimwear or a light rash guard.
Which beach should you choose?
Look for a beach sheltered from the actual forecast waves and wind on your visit. Exposure, currents and entry conditions vary even where water temperatures are similar. Follow local warnings.
Key Largo is the northern gateway to the Florida Keys reef tract, including John Pennekamp Coral Reef State Park. Use this page for water temperature, then check the live forecast for wind, waves and the day's snorkel score. Temperature alone is not a safety rating.
Check the current waves, wind and snorkeling forecast →
A live forecast does not predict a future March. Check again close to your trip.
Waves and wind: recorded-model conditions for March
These figures come from a separately modelled, date-specific wind/wave backfill, not the NOAA SST series. A single observed season is not a climatological likelihood or a guarantee of safe conditions.
Morning calm hours
42%
Afternoon calm hours
38%
Historical coverage
March 2026
31 valid days
Compare nearby coasts with their own evidence
| Coast | Morning | Afternoon | Period |
|---|---|---|---|
| Bahia Honda | 26% | 25% | Mar 2026 |
| Looe Key | 25% | 19% | Mar 2026 |
| Dry Tortugas | 21% | 16% | Mar 2026 |
A “calm hour” meets fixed modelled wave/wind thresholds; neither visibility nor local currents, entry conditions or actual beach safety is measured here. Periods may differ by coast.
Data source and limitations
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature; 2022–2025. Marine model grid near 25.09, -80.45. Based on 3 yearly monthly means and 2232 recorded samples. Source methodology.
Modelled sea-surface temperatures do not establish underwater visibility, wildlife, calm currents or safe entry.