The data of the period between 1901-1950 are mainly from the climate station of Debrecen-Pallag. This station was established in 1868, operated by the Economic High School and it was one of the elements of the measuring network in Hungary. We have no information about its first exact allocation but it was probably not far from the so-called tobacco garden (drying buildings) where it was operated from 1912 (47º35’44”N; 21º38’43”E). Due to the battles of the 2nd World War the station was destroyed in September 1944 and the measurements were launched again only in November 1946. The climatic measurements of the University of Debrecen, Faculty of Meteorology supplemented the data of the missing two years. This station was established in 1928 in the neighborhood of the Sports Ground of the University and is about five km towards to south from the station in Pallag (47º33’24”N; 21º36’58”E). During the war its measurements were suspended only for a short time (the data were supplemented with the help of the stations in the vicinity).

The second half of the data series is from the station operated by OMSZ at the airport of Debrecen (47º29’44”N; 21º37’48”E). The station was removed twice within the airport: on 20 April 1960 and on 1 August 1995. Both changes in allocation had much less effects on the conditions of measurements than the removal from Pallag. While within the airport the maximum movement was 1.6 km and the environmental conditions remained the same, the distance between Pallag, which is on the north of the city centre and the airport on the south is 12 km. Temperature and precipitation data of the whole period of hundred years can be found but the instrumental measurements of sunshine duration began only in 1921, thus this data series comprises only 80 years.