Data recorded by automatic weather stations showed that surface air temperatures during the summer of 2013 were near the long-term average, even though the west coast of Greenland saw unusually warm temperatures during the spring. The west coast saw the warmest March on record since 1948 in 2013 at 13.9°F (7.7°C) above the 30-year baseline. Unlike the previous six summers, however, 2013 was characterized by a positive phase of the North Atlantic Oscillation, which diverted warm, southerly air masses eastward away from Greenland. The mean value of the oscillation was 0.88 during summer 2013, the highest such value since 1996’s 0.92. The weather pattern made way for a northerly airflow that promoted wetter and cloudier weather than normal in the western part of the country. Scientists attributed this oscillation as a potential reason for the drop in melting compared to last year.
More information can be found in the Greenland Ice Sheet chapter of the Arctic Report Card: Update for 2013.