( i8 ) 



March to October, while for the rest of the year is-considerab - 

 ly. -above the average. 



. As to the seasonal distribution of clouds I can clearly say 

 that in Ura-Nippon, it is almost uniform through all seasons 

 except winter and fs^r less than the amount in winter. On the 

 contrary, the sky is most cloudy in the summer and clearest 

 in the winter in the Pacific Belt,, \yhilein the spring and autunin 

 it falls between the two extremities. 



In the west coast of Japan the conditions of cloudiness 

 are uniformly distributed between the winter, spring and sum- 

 mer, the autumn being the clearest season. In the Inland Sea 

 Region, the spring and summer are rather cloudy, and the 

 other seasons clearer. 



The variations of relative humidity show a parallelism to 

 those of the average temperatures of the respective places. It 

 is great in summer and small in winter. The maximum falls 

 in August, and the minimum in January. The average of the 

 two extremes amounts to some 1 5 mm. in the south and dimi- 

 nishes gradually northwards to 13 mms. in Hokkaido. 



The annual variations of humidity show two maximum 

 and minimum in Ura-Nippon, while in Omote-Nippon, there is 

 only one minimum a.nd maximum, as shown in the following 

 table:— 



Thus, one can see the great humidity of our climate, Hok- 

 kaido standing highest in the scale as shown in the table. 

 Xhis phenomenon is caused by cooling effect of the " Oya* 

 ^hiwp," a cold cyrrent sweeping parallel to and along the 



