Baffin Bay pack ice. Winds are predominantly north-western through the whole year. South-eastern and eastern winds are common in July and August. Between May and July (sometimes April), a significant portion of navigable open water (polynya) forms at the extreme north of the bay, presumably due to the relatively warm Greenland Current. With an area of about in summer, it is the largest polynya of the Canadian Arctic and covers the Smith Sound between the Ellesmere Island and Greenland. This polynya has a stable position and existed for at least 9,000 years. It was first described in 1616 by William Baffin and
Investigator Strait boundary with Gulf St Vincent is the line from Troubridge Point on Yorke Peninsula to Cape Jervis on Fleurieu Peninsula. Its boundary with Backstairs Passage is the line from Cape Jervis on Fleurieu Peninsula to Kangaroo Head (west of Penneshaw) on Kangaroo Island. Flinders noted that Backstairs Passage is a body of water separate to Investigator Strait. The boundary between the strait and Nepean Bay on the north-east coast of Kangaroo Island is a line between Point Marsden and Kangaroo Head. The Strait’s western boundary by definition is the line from Cape Spencer on Yorke Peninsula to Cape Borda on