Field observations of Easter weather on Snowdon from 1969 to 2010

Abstract Students from Bangor University made weather observations on the slopes of Snowdon in their Easter holidays from 1969 to 2010. The air temperature decreased with altitude at a rate of about 10 degCkm−1, close to the dry adiabatic lapse rate, although the gradient was less when raining. Water temperatures also decreased with height but wind speeds, on average, increased. The eastern flank of the mountain was noticeably wetter and less windy than the north. Over the four decades, air temperatures increased by an average of 1.6 degC, equivalent to the mountain shrinking by 160m, based on the observed lapse rate.