The objectives of the study was to find out the changing trend of major climatic variable (temperature and rainfall) over the period and forecast for succeeding five years (up to 2017) as well as to explore its influences on rice yield in Mymensingh district of Bangladesh. The study was carried out on gathering data from Weather Yard, Bangladesh Agricultural University (BAU) and 8 annual issues of Bangladesh Bureau of Statistics (BBS) from 1975 to 2012. Different statistical methods were employed to attain the results by gathered data. Firstly, from the descriptive statistics it was found that climate variables and rice yield is changing over period and from trend analysis it was found that trend of average annual maximum temperature and average annual rainfall are decreasing. Whereas, average minimum temperature and average mean temperature trend are increasing overtime. From the forecasted value its rate of change was also calculated. It was found from the linear regression analysis that average annual maximum temperature and average annual rainfall had significant negative influences on rice yield while, average annual mean temperature had significant positive influence on rice yield of the study area. The changing trend of climatic variables was highly fluctuating and not favorable for better crop production as well as shows some indication of desertification for the study area.