Lake Onega is relatively cold, with temperatures below for half of the year and average summer temperatures of about . The catchment area of drains into the lake via 58 rivers and more than 110 tributaries, including the Shuya, Suna, Vodla, Vytegra and Andoma. The only outgoing River Svir, which marks the southern boundary of Karelia, runs from the southwestern shore of Lake Onega to Lake Ladoga and continues as the Neva River to the Gulf of Finland. The White Sea–Baltic Canal runs through the lake from the White Sea to the Baltic Sea. The Volga–Baltic Waterway connects Onega Lake with the
Arkhangelsk Oblast The oblast is administratively divided into six cities and towns under the oblast's jurisdiction (Arkhangelsk, Koryazhma, Kotlas, Novodvinsk, Onega, and Severodvinsk), one city under the federal jurisdiction (Mirny), twenty-one districts (one of which is Novaya Zemlya), and two island territories (Franz Josef Land and Victoria Island). Another six towns (Kargopol, Mezen, Nyandoma, Shenkursk, Solvychegodsk, and Velsk) have the status of the towns of district significance. Nenets Autonomous Okrug, which is administratively subordinated to the oblast, is administratively divided into one district (Zapolyarny District) and one town of okrug significance (Naryan-Mar). Huge areas within the limits of the oblast are included