The Baltic Sea is a brackish inland sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands.
The following countries have outlets on the Baltic Sea (moving clockwise)
Much of the Baltic sea ices over in the winter so cruises are limited to the summer season.
On Shipboard, the air temperature is dominated by the sea temperature which, in the late spring is dependent upon the melting of the Winter ice. By July air temperatures reach 16 or 17 deg C (61-63 F) rising to 22 deg (72 F) near mainland coasts. Day time temperatures over land can, on occasion, be as high as 30 deg C (86 F).
In the late Spring and Summer, following the ice melting, sea temperatures rise rapidly. Around the Danish islands and in the Southern Baltic near Kaliningrad, 10 or 11 deg C (50-52 F) in May becomes 17 to 18 (63-64 F) by August. To the south of Gotland temperatures of 5 or 6 (41-43) in May becomes about 16 degrees (61 F) in August. In the Gulf of Finland a temperature average of just 1 deg C (34 F) in May rises to 16 (61 F) or higher approaching St Petersburg in August.
Thunderstorms are likely during any time of the year. Typical numbers of days per month during May to August with thunderstorms range from 2 or 3 at Copenhagen and Stockholm to 4 or 5 towards the east near Riga, St Petersburg and Helsinki.
Cruise Ships frequent these waters with tours that last 10 to 14 days depending on what countries you want to visit. Often one ship will travel the Baltic Sea alternating between a clockwise and counterclockwise traversal of the sea. Somewhat longer cruises may venture out into the North Sea.