Impact of climate change is very complex because it occurs in various sector of live such as health, agriculture, forestry and transportation. Extreme weather is one of climate change effect, that is a weather condition or phenomenon above normal that occurs in a particular area with short term duration, for instance average temperature condition in some place is 33 0C then change dramatically to 33-47 C with rainfall greater than 100 mm and wind speed more than 34 knot. Extreme Value Theory is one of statistical methods which is used for the description of rare events. This research evaluates the performance of Block Maxima approach for modelling average temperature in East Java and estimate how high return level of average temperature will be happened in 100 months later.