Knowledge of the seasonal climate regime for a region is of paramount importance, because urban and rural planning actions are impacted in different forms and intensities. In this sense, the objective is to determine the influence of El Niño and La Niña phenomena on precipitation, evapotranspiration, deficiency, water surplus and temperature in Bom Jesus-PI. We used series of meteorological data from the National Institute of Meteorology, with annual temperature and precipitation, the water balance was effected. The dispersion analysis of the mean thermal and rainfall values was used in the evaluation of the sinotic elements in relation to the El Niño/La Niña phenomena, using the evaluations of extreme values and climatic anomalies, charact...