To assess the thermic development of the Baltic Sea surface water, the IOW uses satellite data daily provided by the Federal Maritime and Hydrographic Agency since 25 years. Within this period, there was no year like 2014 with all mean monthly values 1 – 3 °C above the long-term monthly average. Even the current mean weekly values of December 2014 show that the SST is still nearly 2°C higher than the long-term average of December values.

The Central and Northern Baltic Sea show a similar situation. Negative anomalies were registered only from the Gotland Basin to the Bothnian Sea during July and less significant anomalies than those measured in the Western Baltic Sea were also registered during other months, while in July and August the entire Baltic Sea was characterized by rather homogeneous temperatures of approximately 18 – 20 °C leading to extreme anomalies of 3 – 5 °C in the Northern Baltic Sea in July.

In summary, this will cause a very high mean annual value for the entire Baltic Sea, which presumably will top the so far warmest year 2008 which exceeded the mean value of the period 1990 – 2012 by +0.9 .