Monthly mean frequencies of sea fog occurrence were averaged for groups of stations in each sea to examine their seasonal variations from 1986 to 1995 (Fig. 3).
Eleven stations from Sochongdo to Sohuksando, were used for the west sea, eight from Seogwipo to Pusan, for the south sea, and five from Changgigap to Kojin, for
the east sea. The average rate of occurrence shows that most sea fog occurs in all seas in summer. Fog days are less than one day from September through February and at their peak in all seas in July. This is similar to the structure of sea fog occurrence around the United Kingdom,where sea fog occurs most commonly in spring and early summer (Roach 1995).