Because of the difficulty of data collection, little is known about the climate and hydrology of high mountain basins. Following the development of an automatic weather station (AWS) in the 1960s for use in upland Britain, the Institute of Hydrology is now engaged in developing an AWS for operation in more mountainous areas. To this end, and using the summit of Cairn Gorm in Scotland as a proving-ground, investigations are being carried out into methods of preventing ice accretion, new ways of deploying temperature sensors, alternative ways of exposing radiation sensors consistent with the deicing techniques, the sensing of wind by static sensors, the choice of the most appropriate method of sensing humidity, and the measurement of rain and snowmelt. This paper describes these new techniques.