A milking installation comprises a compressed air system with a compressed air line, a pneumatically controllable cylinder and a compressed air pump for supplying compressed air for the cylinder. The compressed air system comprises a dew point sensor for measuring the dew point of the compressed air and for emitting a dew point signal that is representative of the dew point. The milking installation may comprise or form part of a milking robot for automatically connecting teat cups to the teats of a dairy animal.