The species diversity and the total cell numbers were low in the Skagerrak but higher in the Kattegat. Overall diatoms dominated at all stations and among the larger cells. Pseudo-nitzschia* was common at most stations. The smaller cells had a dominance of cryptomonads and Emiliania huxleyi. The integrated chlorophyll concentrations were within normal with only one exception, at Släggö, where the integrated chlorophyll concentrations were below normal for this month. Winter conditions prevailed in the Baltic Proper phytoplankton world this month. Only at BY2 in the southwestern Baltic, the phytoplankton diversity was fairly high. At all other stations, the number of species and total cell numbers were generally low. The integrated chlorophyll concentrations (0–10 and 0–20 m) were within the normal range for this month at all stations in the Baltic Proper, except at BY1 where they were well above one standard deviation.