Winter (December-January-February)In winter (December-January-February), the Siberian High develops over the Eurasian Continent and the Aleutian Low develops over the northern North Pacific. Prevailing northwesterly winds cause the advection of cold air from Siberia to Kinki and bring heavy snowfall to the Sea of Japan side of Kinki (upstream of mountainous land) and sunny weather to the Pacific side (downstream of mountainous land). Spring (March-April-May)In spring (March-April-May), migratory cyclones and anticyclones that alternately move eastward prevail across Japan. Temperature increases (decreases) in front (back) of cyclonic systems due to warm southerly (cold northerly) flow. Temperature in Kinki rises gradually with large short-term variations. Kosa (Aeolian dust transported from deserts or semi-arid areas of the Asian continent by westerly winds, resulting in yellow skies and haze) is sometimes observed over Kinki. The sunshine duration is long in the second half of spring due to the predominance of anticyclonic systems. Summer (June-July-August)The period from early June to the middle of July is the rainy season (known as the Baiu). Its precipitation is caused by a stationary front, called the Baiu front, which forms where a warm maritime tropical air mass meets a cool polar maritime air mass. In the second half of summer, the North Pacific High extends northwestward around Japan, bringing very hot, humid, and sunny conditions, sometimes accompanied by temperatures of 35°C or above, to Kinki. Monthly precipitation amounts for August are small in some areas around the Seto Inland Sea. Autumn (September-October-November)In autumn (September-October-November), temperatures in Kinki fall gradually. Monthly precipitation amounts over Kinki are large in September due to the active autumnal rain front and tropical cyclones. The Kii Peninsula (the southern part of Kinki) has one of Japan's highest rainfall totals. In October, the frequent passage of anticyclonic systems brings sunny conditions and refreshing air to Kinki. The frequencies of cold northwesterly flow across Japan shows an increasing tendency in November. |