Mljet Water Temperature
Updated Tue 14:53 (Europe/Zagreb)
Croatia · Forecast updated Sep 22, 2026, 14:53 UTC · refresh delayed
Current Sea Temperature
26.1°C
79.0°F
Warm water
Valid Sep 22, 2026, 14:53 (Europe/Zagreb). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
1.1°C above
The typical September average is 25.0°C (77.0°F) from the historical baseline.
Recent trend
Cooling by 0.9°C
Seven-day average: 26.7°C, versus 27.6°C in the prior seven days.
What to wear
Warm water
Most people are comfortable in swimwear or a light rash guard.
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 Mljet, typical monthly averages range from about 14.8°C (58.6°F) in February to 26.2°C (79.2°F) in August.
Over the past 30 days, the average sea temperature in Mljet has been 27.9°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Mljet, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 15.2–16.1°C | 15.7°C / 60.3°F |
| February | 14.6–15.0°C | 14.8°C / 58.6°F |
| March | 14.6–15.6°C | 15.2°C / 59.4°F |
| April | 15.6–17.1°C | 16.3°C / 61.3°F |
| May | 18.5–19.4°C | 19.0°C / 66.2°F |
| June | 23.2–24.3°C | 23.7°C / 74.7°F |
| July | 25.2–26.3°C | 25.9°C / 78.6°F |
| August | 25.5–27.0°C | 26.2°C / 79.2°F |
| September | 24.4–25.7°C | 25.0°C / 77.0°F |
| October | 20.6–23.2°C | 22.0°C / 71.6°F |
| November | 18.4–20.6°C | 19.4°C / 66.9°F |
| December | 16.9–17.2°C | 17.1°C / 62.8°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (42.79, 17.54). 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.
Mljet in January
Typical January water temperature near Mljet is 15.7°C (60.3°F), with yearly monthly means from 15.2–16.1°C.
Mljet in February
Typical February water temperature near Mljet is 14.8°C (58.6°F), with yearly monthly means from 14.6–15.0°C.
Mljet in March
Typical March water temperature near Mljet is 15.2°C (59.4°F), with yearly monthly means from 14.6–15.6°C.
Mljet in April
Typical April water temperature near Mljet is 16.3°C (61.3°F), with yearly monthly means from 15.6–17.1°C.
Mljet in May
Typical May water temperature near Mljet is 19.0°C (66.2°F), with yearly monthly means from 18.5–19.4°C.
Mljet in June
Typical June water temperature near Mljet is 23.7°C (74.7°F), with yearly monthly means from 23.2–24.3°C.
Mljet in July
Typical July water temperature near Mljet is 25.9°C (78.6°F), with yearly monthly means from 25.2–26.3°C.
Mljet in August
Typical August water temperature near Mljet is 26.2°C (79.2°F), with yearly monthly means from 25.5–27.0°C.
Mljet in September
Typical September water temperature near Mljet is 25.0°C (77.0°F), with yearly monthly means from 24.4–25.7°C.
Mljet in October
Typical October water temperature near Mljet is 22.0°C (71.6°F), with yearly monthly means from 20.6–23.2°C.
Mljet in November
Typical November water temperature near Mljet is 19.4°C (66.9°F), with yearly monthly means from 18.4–20.6°C.
Mljet in December
Typical December water temperature near Mljet is 17.1°C (62.8°F), with yearly monthly means from 16.9–17.2°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 | 21.0°C / 69.8°F | 24.3°C / 75.7°F | 27.9°C / 82.2°F |
| July | 24.8°C / 76.6°F | 26.2°C / 79.1°F | 28.3°C / 82.9°F |
| August | 26.3°C / 79.3°F | 27.8°C / 82.1°F | 29.3°C / 84.7°F |
| September | 25.2°C / 77.4°F | 27.4°C / 81.3°F | 29.2°C / 84.6°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 Mljet
Forested national-park island with saltwater lakes and clear sheltered bays.
- Area
- Dubrovnik-Neretva
Mljet Water Temperature: Common Questions
What is the water temperature in Mljet today?
The current sea surface temperature near Mljet is 26.1°C (79.0°F). Over the last 30 days, the average has been 27.9°C.
When is the water warmest in Mljet?
The water is typically warmest in August, at around 26.2°C (79.2°F) in the 2023–2025 historical baseline.
When is the water coldest in Mljet?
The water is typically coldest in February, at around 14.8°C (58.6°F) in the same historical baseline. A wetsuit is usually recommended during this period.
Can you swim in Mljet today?
At 26.1°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 Mljet.
View Snorkel Forecast →