It's Not The Artic Bro . Black Sea Temps WinterIn winter, water temperature ranges from 31 °F (−0.5 °C) in the northwest to about 48 to 50 °F (9 to 10 °C) in the southeast. The winter cooling forms an upper mixed layer extending to depths of about 160 to 330 feet (50 to 100 metres), with temperatures at the lower boundary of about 44 to 46 °F (6.5 to 8 °C).