The sea ice cover of the Southern Ocean reached its yearly maximum extent on October 6, 2015. After three years of consecutive record high peak extents, this year’s extent of 7.27 million square miles falls roughly in the middle of the record of Antarctic maximum extents compiled during the 37 years of satellite measurements. This year’s maximum extent occurred fairly late: the mean date of the Antarctic maximum is September 23 for 1981-2010. The growth of Antarctic sea ice was erratic this year and scientists believe that the strong El Niño event forming over the eastern equatorial Pacific Ocean had a role in the behavior of the sea ice cover. El Niño causes higher sea level pressure, warmer air temperature and warmer sea surface temperature in areas of Antarctica, affecting the sea ice distribution. Watch the video to see the evolution of this year's Antarctic sea ice cover, from its austral summertime minimum to its wintertime maximum.