AbstractUsing June–August surface meteorological measurements for 2004–10 we found that the duration of the summer melt season at elevations of 1800, 1300 and 1000 m a.s.l. on Devon Ice Cap, Canada, increased at a rate of 3.4 (p < 0.1; weak significance), 6.1 (p< 0.01) and 8.8 (p < 0.05) days a−1, respectively. The calculated surface melt rate at 1300m a.s.l. increased from 74 to 133 cm w.e. a−1 between 2007 and 2010. These changes are linked to two types of change in the Arctic atmospheric circulation. Strengthening of the 500 hPa ridge over the Arctic in June–July resulted in increases in both the advection of warm air into the region and the occurrence of cloud-free conditions over the ice cap, causing the available melt energy to increase by 4–24% relative to June–July 2007–10 mean conditions. More frequent southwesterly low-pressure systems in August after 2004 accounted for a 12–38% increase in available melt energy relative to the August 2007–10 daily mean due to advection of warm air into the Arctic, reduced incoming shortwave radiation and increased net longwave radiation. This delayed the timing of freeze-up by an average of 5.5 days a–1 (p < 0.05) at the three sites over 2004–10.