What is the water temperature in the Baltic Sea today? Is the sea already 18 degrees and suitable for swimming? Or are you planning a seaside holiday and want to know if the bathing area will be comfortable?
Current water temperature in the Baltic Sea - map and real-time data
The current water temperature in the Baltic Sea is monitored by online services and measuring stations. SST (Sea Surface Temperature) maps are most commonly used; they show the sea surface temperature in real time. Data are published, among others, by IMGW-PIB. On the maps you can check:
- temperature at 0 m (SST),
- temperature at 5 m,
- temperature at 10 m,
- differences at the shore vs the open sea.
This is important because the temperature near the shore can differ from that in the open sea. In shallow areas the water warms up faster, while in deeper parts of the basin and with different bathymetry the thermal gradient can be pronounced. It's also worth following the weather forecast for the coming days - strong winds can change the water temperature even within a day.
If you are planning a seaside holiday and care about comfortable swimming, check the conditions in your chosen town before arriving.
What is the average water temperature in the Baltic Sea in each month?
The average water temperature in the Baltic Sea varies significantly throughout the year. The summer season is relatively short, but in summer the sea can reach really pleasant temperatures.
Indicative temperatures by month:
- January–February: 0–3°C
- May: 8-12°C
- June: 14-18°C
- July: 18-22°C
- August: 19-22°C
- September: 15-18°C
At the peak of the summer season the average water temperature in the Baltic Sea is about 18 degrees Celsius. In warmer years it is higher, especially in shallow bays.
In recent years a thermal anomaly related to climate warming has been observed. As a result, in summer the water temperature exceeds 20°C more often than a decade ago.
Why does the Baltic warm up in layers?
In the summer season thermal stratification occurs. This means that the sea's water arranges itself in layers:
- warm surface layer,
- colder deeper layer,
- between them the thermocline - a zone of rapid temperature change.
This thermal gradient means that the surface water temperature can be 20°C while a few meters below it is noticeably cooler. If you see that the water temperature in the Baltic is about 18–20°C and sunny weather is forecast - it's a good time to plan a trip.
Baltic temperature in the most popular towns
The Baltic Sea temperature varies depending on location:
- Gdańsk - the Gdańsk Bay favors faster warming.
- Gdynia and Sopot - similar conditions to Gdańsk.
- Świnoujście - the western part of the coast can be warmer in the season.
- Hel - upwelling is possible, i.e., an inflow of cold water from the depths.
- Jastrzębia Góra - open sea, greater temperature variability.
- Kołobrzeg, Mielno, Ustka, Łeba, Władysławowo, Międzyzdroje - differences depend on wind and basin depth.
Puck Bay, thanks to its shallower depth and specific bathymetry, warms up faster than the open sea. It's therefore worth checking both the nearshore temperature and the temperature in the open sea.
Why is the Baltic Sea water temperature variable?
Sudden cooling of the water is often the effect of upwelling. Strong wind pushes warm surface water away, and colder water from the depths flows in to replace it. Other factors affecting temperature:
- thermohaline circulation,
- halocline (salinity differences),
- coastal microclimate,
- North Atlantic Oscillation,
- climate change.
High water temperature in summer also favors cyanobacterial blooms. Even if the sea is 20°C, the presence of cyanobacteria can prevent swimming.
When is the Baltic Sea water temperature best for swimming?
Minimal comfort for swimming begins for most people at 18°C. That's when most bathing sites record the most visitors.
- 18°C - you can swim, although people sensitive to cold will feel chilly.
- 20°C - a comfortable water temperature for adults.
- 22°C - very pleasant also for families with children.
In August the high water temperature makes sea bathing most enjoyable. In winter, the Baltic attracts winter swimming enthusiasts.
Swimming comfort on the Baltic - where to choose a calm bathing area?
Near Jastrzębia Góra there is Rosevia Resort & SPA - a resort offering a private beach, which is rare on the Polish coast.
If you check the Baltic Sea water temperature to decide whether it's a good time to swim - it's worth choosing a place where even at 17–18°C the comfort of relaxation remains high. Intimate conditions, lack of crowds and a pool as an alternative when the sea temperature is lower make a seaside holiday more predictable.
FAQ - Baltic Sea water temperature
What is the current water temperature in the Baltic Sea?
The current water temperature in the Baltic Sea depends on location and weather. It's best to check an SST map or IMGW data, which show temperature in real time.
How many degrees is the water in the Baltic Sea in August?
In August the water temperature in the Baltic Sea most often ranges from 19-22°C, and the sea is the warmest during the season.
Is 18 degrees a good temperature for swimming?
For many people 18°C is the minimal comfort for swimming. Water at this temperature allows swimming, although not everyone will consider it warm.
Why does the water in the Baltic suddenly cool down?
Sudden cooling is usually the result of upwelling. The Baltic Sea water temperature can drop by several degrees within a single day.
Does the Baltic freeze in winter?
In shallow areas the sea can partially freeze. The water temperature in the Baltic Sea in winter drops to around 0°C.
Where is the water in the Baltic warmest?
The highest water temperatures usually occur in shallow bays, such as Puck Bay or Gdańsk Bay.
Do cyanobacteria affect the possibility of swimming?
Yes. Even if the water temperature in the Baltic Sea is high, the presence of cyanobacteria can temporarily close a bathing site.
If the water temperature in the Baltic Sea is 18–20°C and the weather is favorable, it's an ideal time for a trip. And if you want to be sure that even with a slightly lower sea temperature your stay will be comfortable, choose a place that offers more than just beach access.
