May saw a sharp decrease in Arctic sea ice cover, based on satellite observations. The average ice cover for the month was about 13 million square kilometers, 500,000 square kilometers less than the 30-year average. The rate of icemelt averaged 46,000 kilometers per day, the fastest rate recorded. The graph above indicates the area of Arctic sea ice is now below two standard deviations of the mean ice coverage observed since 1979. Two standard deviations make up about 95 percent of the data, placing the May data in the skinny “tail” of the bell curve.

Temperatures were 2 to 5 degrees Celsius higher than average over the Arctic while central North America saw colder than average temperatures.

Source: June 8, 2010 Update, National Snow and Ice Data Center