Hsummer In the Northern Hemisphere, the deepest winter is in Antarctica. Much of the continent is in perpetual darkness, battered by winds that regularly exceed 100 miles per hour and temperatures that drop below -60 degrees Celsius. It is usually surrounded by a vast, growing expanse of sea ice, which usually reaches its greatest extent around September. But Antarctica is currently, according to satellite data,  exceptionally little ice — the lowest ever recorded in June. What does this mean for the rest of the world?