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
Primorsky District, Arkhangelsk Oblast first-level administrative division of Russia kept changing. In 1930, the okrug was abolished, and the district was subordinated to the central administration of Northern Krai. In 1936, the krai was transformed into Northern Oblast. In 1937, Northern Oblast itself was split into Arkhangelsk Oblast and Vologda Oblast. Primorsky District remained in Arkhangelsk Oblast ever since. The location of the administrative center of the district was moved several times until Arkhangelsk finally became the center. On December 17, 1940, Belomorsky District was established on the Onega Peninsula, in the areas which previously were parts of Primorsky and Onezhsky Districts. The administrative