The Amnokkang, Tumangang, Hangang, Kumang, and Naktonggang all exceed 400 km in length. The Amnokkang and Tumangang form the international boundaries between China and Russia and flow into the Yellow and East Seas respectively. Korea's climate is East Asian monsoonal. Climate is influenced more by proximity to the largest continent in the world than it is by the water surrounding the peninsula. The range in temperature is greater in North Korea than South Korea.
Cyclones are vital to Korea's rice fields.
In March and April cyclones are common. Typhoons originating in the East Philippines hit the Korean peninsula in August every two three years. Heavy flooding off the South Sea coast is common in late summer and early autumn. The winters are very cold with an average temperature of 32 degrees. The east coast has wide strips of Alluvial beaches.