Abstract
During the “Baiu” season, cold and humid easterly wind locally called “Yamase” often prevails over Northeastern Japan. The distribution of frequency of cloudy weather (Fig. 1) or rainy weather (Fig. 2) under such a condition was obtained. Fig. 1 shows the area of cloudy weather extends from the east, and Fig. 2 shows that rainy weather often appears along the Pacific coast and Ou-and Kitakami mountain ranges. Both types of the distribution are influenced by the higher part (>750m) in Ou and Kitakami ranges.
