In Babylon Governorate there exists a single meteorological observing stationwhich is located at Hilla city. An observation at this station is a point observation. Inorder to determine variation of rainfall and of evaporation in Babylon Governoraterecords at nearby stations should be considered. These stations are Baghdad, Kerbalaa,Najaf, Diwaniya, Kut, Hai, and Ramadi stations which are located outside the boundaryof Babylon. In this study the Thiessen polygons method is used to define zone ofinfluence for each of these stations and, hence, monthly mean rainfall are computed. Itis found that the monthly mean rainfall are 15.159, 18.08, 22.719, and 15.339 mm/month for the winter months November, December, January, and February respectively. The monthly mean evaporation are found to be 266.912, 288.057, and259.936 mm/month for the summer months Jun, July, and August respectively.