Frequency of showers and floods show an increasing trend in recent year in the world. Role of climate changing on frequency of natural hazardous depends on topographic structure, vegetation cover, land use- land surface classification and urbanization. This paper covers analyses of spatial and temporal variations of air temperature and precipitation at four selected stations (Bah？ek？y, Florya, G？ztepe and ？ile) in European and Asian parts of Istanbul. Mean air temperature variations show an increasing trend between 3% and 5% at G？ztepe and Florya. The extreme increasing ratio of monthly maximum air temperature values (6%) is observed at ？ile. Increasing trends of monthly total rainfall rates at Bah？ek？y and ？ile are 10% and 17% respectively. Role of urbanizations on temporal and spatial variations of daily, monthly averages and extremes of variables have been statistically evaluated in this paper.