Daily weather observations measured by students and staff at Halkali Agricultural School (a school opened in 1892 for agriculture and animal husbandry during the Ottoman period) from 1896 to 1917 in Istanbul, Turkey have been transcribed from the original publications into digital form and translated from Ottoman Turkish (the Perso-Arabic script) to English (Latin alphabet). Over 55 thousand observations of daily maximum, minimum and average temperature, rainfall, soil and under soil (0.25m) temperature, humidity, pressure, and wind speed were recovered.