10 
1.2. Statistical characteristics 
The relative frequency of ice occurrence on the 01 st , 11 th and 21 st dates of the months from 
November to April in Szczecin Lagoon (Kamminke, Kamin, Ueckermiinde) and Pomeranian 
Bay (Koserow) is shown in Figure 1.4. The frequency curves in all areas have two maxima. 
The probability of encountering ice in Szczecin Lagoon in November or at the beginning of 
December is very low, and for the Pomeranian Bay it is equal to zero. At the end of December 
and in January, the frequency rises and reaches its first maximum between 11 January and 
1 February. The second maximum is found between 21 February and 1 March. 
Figure 1.4. Relative frequency of ice occurrence in Szczecin Lagoon and Pomeranian Bay 
Table 1.3 contains the frequency distribution of the number of days with ice. In the 
Pomeranian Bay, half of the winters is observed without major ice formation, with maximal 
20 days with ice. There are few winters in which the number of days with ice exceeds 60. In 
Szczecin Lagoon, ice forms every winter, and under extreme conditions, it remains there for 
more than four months. 
Table 1.3. Frequency of winters with different numbers of days with ice 
Area of observation 
No 
ice 
Days with ice 
Number 
of winters 
1-20 
21-40 
41-60 
61-80 
81-100 
101-120 
>120 
Dziwnow, harbour 
5 
5 
9 
3 
3 
0 
0 
0 
25 
Dziwnow, sea area 
5 
11 
6 
2 
2 
0 
0 
0 
26 
Szczecin, harbour 
4 
10 
4 
5 
4 
3 
0 
0 
30 
Trzebiez, Rostoka Odrzahska 
4 
0 
5 
8 
2 
5 
3 
0 
27 
Zalew Szczecinski 
4 
1 
4 
4 
6 
6 
4 
1 
30 
Swinoujscie - Szczecin, fairway 
5 
0 
5 
5 
5 
5 
3 
2 
30 
Swinoujscie, harbour 
4 
5 
6 
6 
5 
4 
0 
0 
30 
Swinoujscie, sea area 
7 
9 
5 
6 
2 
0 
1 
0 
30 
Kamminke, harbour and vicinity 
0 
5 
2 
7 
3 
5 
5 
1 
28 
Ueckermiinde, Szczecin Lagoon 
2 
5 
5 
3 
5 
5 
4 
1 
30 
Kamin, Szczecin Lagoon 
1 
4 
5 
7 
4 
6 
2 
1 
30 
Koserow, sea area 
9 
7 
4 
5 
1 
3 
1 
0 
30