Grand Cayman Water Temperature
Updated Tue 14:53 (America/Cayman)
Cayman Islands · Forecast updated Sep 22, 2026, 14:53 UTC · refresh delayed
Current Sea Temperature
30.1°C
86.2°F
Very warm water
Valid Sep 22, 2026, 14:53 (America/Cayman). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.8°C below
The typical September average is 30.9°C (87.6°F) from the historical baseline.
Recent trend
Cooling by 0.3°C
Seven-day average: 30.9°C, versus 31.2°C in the prior seven days.
What to wear
Very warm water
Swimwear is usually enough; a rash guard adds sun protection.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Grand Cayman, typical monthly averages range from about 26.8°C (80.2°F) in February to 30.9°C (87.6°F) in September.
Over the past 30 days, the average sea temperature in Grand Cayman has been 31.0°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Grand Cayman, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 27.2–27.5°C | 27.4°C / 81.3°F |
| February | 26.6–27.0°C | 26.8°C / 80.2°F |
| March | 27.3–27.8°C | 27.6°C / 81.7°F |
| April | 27.9–28.3°C | 28.1°C / 82.6°F |
| May | 29.0–29.4°C | 29.3°C / 84.7°F |
| June | 29.6–29.7°C | 29.7°C / 85.5°F |
| July | 29.9–30.3°C | 30.1°C / 86.2°F |
| August | 30.6–30.8°C | 30.7°C / 87.3°F |
| September | 30.6–31.3°C | 30.9°C / 87.6°F |
| October | 30.0–30.7°C | 30.4°C / 86.7°F |
| November | 28.8–29.4°C | 29.0°C / 84.2°F |
| December | 28.0–28.3°C | 28.2°C / 82.8°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (19.38, -81.29). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2023–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Grand Cayman in January
Typical January water temperature near Grand Cayman is 27.4°C (81.3°F), with yearly monthly means from 27.2–27.5°C.
Grand Cayman in February
Typical February water temperature near Grand Cayman is 26.8°C (80.2°F), with yearly monthly means from 26.6–27.0°C.
Grand Cayman in March
Typical March water temperature near Grand Cayman is 27.6°C (81.7°F), with yearly monthly means from 27.3–27.8°C.
Grand Cayman in April
Typical April water temperature near Grand Cayman is 28.1°C (82.6°F), with yearly monthly means from 27.9–28.3°C.
Grand Cayman in May
Typical May water temperature near Grand Cayman is 29.3°C (84.7°F), with yearly monthly means from 29.0–29.4°C.
Grand Cayman in June
Typical June water temperature near Grand Cayman is 29.7°C (85.5°F), with yearly monthly means from 29.6–29.7°C.
Grand Cayman in July
Typical July water temperature near Grand Cayman is 30.1°C (86.2°F), with yearly monthly means from 29.9–30.3°C.
Grand Cayman in August
Typical August water temperature near Grand Cayman is 30.7°C (87.3°F), with yearly monthly means from 30.6–30.8°C.
Grand Cayman in September
Typical September water temperature near Grand Cayman is 30.9°C (87.6°F), with yearly monthly means from 30.6–31.3°C.
Grand Cayman in October
Typical October water temperature near Grand Cayman is 30.4°C (86.7°F), with yearly monthly means from 30.0–30.7°C.
Grand Cayman in November
Typical November water temperature near Grand Cayman is 29.0°C (84.2°F), with yearly monthly means from 28.8–29.4°C.
Grand Cayman in December
Typical December water temperature near Grand Cayman is 28.2°C (82.8°F), with yearly monthly means from 28.0–28.3°C.
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 28.9°C / 84.0°F | 29.5°C / 85.0°F | 30.1°C / 86.2°F |
| July | 29.6°C / 85.3°F | 30.2°C / 86.3°F | 31.4°C / 88.5°F |
| August | 29.8°C / 85.6°F | 30.5°C / 86.9°F | 31.2°C / 88.2°F |
| September | 30.1°C / 86.2°F | 31.0°C / 87.8°F | 31.7°C / 89.1°F |
Partial coverage: 4 calendar months with records. Profile calculated from 2735 hourly forecast records across 4 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Grand Cayman
Home to Stingray City and the shallow coral gardens of the North Sound.
- Area
- Grand Cayman
Grand Cayman Water Temperature: Common Questions
What is the water temperature in Grand Cayman today?
The current sea surface temperature near Grand Cayman is 30.1°C (86.2°F). Over the last 30 days, the average has been 31.0°C.
When is the water warmest in Grand Cayman?
The water is typically warmest in September, at around 30.9°C (87.6°F) in the 2023–2025 historical baseline.
When is the water coldest in Grand Cayman?
The water is typically coldest in February, at around 26.8°C (80.2°F) in the same historical baseline.
Can you swim in Grand Cayman today?
At 30.1°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Grand Cayman.
View Snorkel Forecast →