Bangladesh is confronted with a big challenge to mitigate the significant impact of climate change. Due to the climate change, Bangladesh has already experienced average maximum temperature rising, minimum temperature decreasing, rainfall, relative humidity and cloud coverage decreasing resulting frequent and severe floods, tropical cyclone, extensive river bank erosion and drought. This paper focuses mainly to identify the spatial and temporal changes of climatic variables namely temperature, rainfall, humidity and cloud coverage of Bangladesh using data from Bangladesh Meteorological Department (BMD), Bangladesh Water Development Board (BWDB) and Bangladesh Agricultural Research Institute (BARC) at 32 stations and also find out the adverse impacts of climate change especially on natural disasters of Bangladesh. To determine the climatic variability an inclusive meteorological estimation was carried out for the period of 2007-2011 and the results were compared with the period 1987-1991. The results of the climatic variability show that the average maximum temperature is increasing at a rate of 0.03°C per year but the annual minimum temperature is decreasing at a rate of 0.003°C per year. On the other hand, the annual rainfall, relative humidity and cloud coverage decreased by 0.63 mm, 0.013 percent and 0.007 respectively per year. For these climatic changes during the period 1970 to 2013, one hundred thirty four (134) major and minor cyclones hit the coastal regions of Bangladesh and almost two-third (88) of them hit in the period of 1992-2013 which is very alarming for our survival. On the other hand, it shows that the intensity and frequency of extreme flood events have significantly increased and the most extensive floods in the period 1954-2012 occurred after 1986 (1987, 1988, 1998, 2004, 2007) are considered by hydrologists to be at a size expected only once in every 20 years. The floods of 1987, 1988, 1998, 2004 and 2007 and cyclones of 1991, 1997, 2007 and 2009 are direct impact of climate change in Bangladesh.