In the total area of the Federal Republic of German, the year 2000 was the warmest year on record in the past century, at an annual mean temperature of 9.9 °C. Considering only the coastal areas, the year 1990 was generally warmer. On the whole, 2000 was slightly too dry.
November, at temperatures around 8 °C, was very mild and exceptionally dry. Air or ground frost did not occur. Also during this month, sea surface temperatures were significantly too high (average value: 10.3 °C; anomaly: 0.7 K).
December, at monthly mean temperatures between 4.0 and 5.9 °C, was 1.5 - 2.0 K too warm. While the first half of the month was unusually mild with spring temperatures, freezing temperatures prevailed in the second half. In December of this year, the second warmest sea surface temperatures were recorded since 1994.
In November the phytoplankton generally showed the normal seasonal development. In the Wadden Sea area north of Sylt, the diversity of Thalassiosira species (typical winter species) increased strongly. Potentially toxic algae were not observed.
The haddock year-class of 1999, the strongest one in 20 years, dominated the bottom fish fauna off the British coast. In the German Bight, whiting and cod catches were low.
The number of seals in the Schleswig-Holstein Wadden Sea National Park increased over the preceding year and has reached another maximum.
Because of the mild weather, the coastal areas and North Sea estuaries remained ice-free.
November were noticeably too warm (monthly mean temperatures: 6.3 - 7.4 °C) and much too dry.
December was characterized by the unusually warm first half of the month, with temperatures about 5 K above the long-term mean, and a mostly cold second half of the month which could not, however, compensate
the heat surplus (mean temperatures: 3.1 °C in Ueckermünde, 4.6 °C in Westermakelsdorf on Fehmarn). Precipitation of only 20 to 60 mm continued the dry spell of the two preceding months.
In December, the water levels were below the reference series, as in the preceding months. There was no risk of high or low water levels.
With air temperatures in the northern Baltic clearly above the long-term mean in autumn 2000, a major frost period of several days was only recorded in the easternmost part of the Gulf of Finland in the last decade of November.
Over 4 weeks late (on 9/10 December) cold northerly air led to this season's first major new-ice formation in the inner skerries of the Bottenvik north coast. As late as 18 December, permanent frost set in in the northern Baltic. 20 December thus set a new record for the latest beginning of the ice season.
In early November, a phytoplankton maximum was observed consisting of the species Ceratium tripos, Ceratium fusus, and Dactyliosolen fragilissima at the measuring station "Seebrücke Heiligendamm". In mid-November, Coscinodiscus species (mostly C. granii) caused a chlorophyll-a maximum. After a biomass minimum
in early December, the phytoplankton biomass increased again toward the end of the year, mainly due to diatom growth (Pseudonitzschia cf. pungens, Chaetoceros curvisetum) and dinoflagellates (Ceratium tripos).
Because of oxygen deficiency in the Arkona Sea and Bornholm Sea in late October/early November, hardly any macrozoobenthos was found. At the Fehmarnbelt station, Ophiura albida occurred in large quantities. Saduria entomon was abundant in the southern Arkona Sea.