The dataset includes digitized and rescued monthly rainfall records collected from various stations in Istanbul by foreign scientists, engineers, and officials during the last century of the Ottoman Empire, from 1856 to 1917 with long-term monhtly rainfall (1912-2023) from Kandilli Observatory and Turkish State Meteorological Service.Observatories in Istanbul:Observatory,Latitude,Longitude,Elevation(m)Gulhane,41.0113,28.9793,35Halkali,41.0335,28.7883,119Haydarpasa,41.0013,29.0210,34Kandilli,41.0637,29.0604,133Ortakoy,41.0479,29.0228,32Pera,41.0278,28.9761,51Bebek,41.0768,29.0421,50Erenkoy,40.978,29.091,60Florya,40.9758,28.7865,35