East Siberian Sea runoff into the East Siberian Sea is relatively small at about 250 km/year that makes only 10% of the total runoff in all the Arctic seas of Russia. The largest contribution is from the Kolyma River at 132 km, followed by the Indigirka River at 59 km. Most runoff (90%) occurs in summer; it is concentrated near the coast, owing to the weak river currents, and therefore does not significantly affect the sea hydrology. The water exchange between the neighboring seas is as follows. The annual outflow to the Laptev Sea, Chukchi Sea and Arctic Ocean is 3,240, 6,600 and
East Siberian Sea 11,430 km, respectively; while the respective inflow values are 3,240, 8,800 and 9,230 km. The surface water temperature decreases from south to north. In winter it varies between −0.2 and 0.6 °C at the river deltas and from −1.7 to −1.8 °C in the northern sea part. In summer, it warms to 7–8 °C in the bays and inlets and to 2–3 °C in the ice-free sea zones. Surface water salinity increases from southwest to northeast. In winter and spring, it is 4–5‰ (parts per thousand) near the deltas of the Kolyma and Indigirka rivers. It increases to 28–30‰ in