April 2015 was marked by a fairly rapid decline during the first week of the month, little change during the middle of the month, and then a steep decline over the final week. Overall, extent decreased 862,000 square kilometers (333,000 square miles).
April was marked by higher than average 925 hPa air temperatures (1
to 3 degrees Celsius or 2 to 5 degrees Fahrenheit) throughout the
Arctic, except for Greenland and the Canadian Archipelago where
temperatures were 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit)
below average. Temperatures were 6 to 8 degrees Celsius (11 to 14
degrees Fahrenheit) higher than average in the Kara Sea, linked
to unusually low sea level pressure over the North Atlantic. Associated
wind patterns also resulted in strong warming over the Eurasian Arctic.