Duluth, MN was one of the nation's first weather observing sites. Weather observations from 1871 to 1959 were taken at the origonal National Weather Service office located in downtown Duluth, on the shore of western Lake Superior.
In 1940, the office was moved 6 miles up steep terrain, an elevation change of around 600 ft, to the Duluth Airport. Between the years of 1941 and 1959, weather observations were taken at both locations. Since 1959, the official climate observations for Duluth have been taken at the National Weather Service Office located near the Duluth International Airport.
Although weather records exist from the original observing site in downtown Duluth, the threaded dataset only looks at the weather observations taken at the Duluth Airport during the overalp period.
Snowfall was not part of the daily climate record until 1875. Thus, the All-Time snowfall records are from 1875 to present, whereas the Airport snowfall records are from 1943 to present. The snowfall records also have an overlap from 1943-1959 where snowfall was measured at both locations.