The Mount Washington Observatory was built on the summit in 1932 through a group interested in and noting the worth of a research facility at that demanding location. The observatory's weather data have accumulated a climate record since. Temperature and humidity readings have been collected using a sling psychrometer, a simple device containing two mercury thermometers. Where most unstaffed weather stations have undergone technology upgrades, consistent use of the sling psychrometer has helped provide scientific precision to the Mount Washington climate record.