Baltic Sea water temperature
Baltic Sea, Mariehamn (Åland) · Sea/Coast
The current water temperature at Baltic Sea is 14.7 °C (as of September 20, 2026, source: Open-Meteo marine model).
The sea lags the air by weeks: the warmest water often arrives after the warmest days. Measured buoy values show this honestly.
Water quality
EU classification: excellentMeasurement series & statistics
This measurement series includes 609 data points since July 22, 2026.
Lowest recorded value: 14.6 °C on September 20, 2026 · highest value: 18.5 °C on August 4, 2026.
In September, temperatures have ranged between 14.6 °C and 17.7 °C.
The current value is 1.5 °C below the September average of this series.
Nearby waters
More measuring points: Baltic Sea
Frequently asked questions
Can you swim at Baltic Sea right now?
The current water temperature is 14.7 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Baltic Sea?
Currently 14.7 °C (updated continuously).
How warm is at Baltic Sea in September?
In September, the water temperature recently averaged 16.2 °C.
When is the water warmest at Baltic Sea?
Across the measurement record, July is on average the warmest month (17.8 °C).
How is the water quality at Baltic Sea?
The official classification is: excellent.
