Buildings are designed for a specific climate yet they often have a lifetime of 100 years. This effect is compounded by the fact that much of the climatic data currently used for design purposes is some 30 years old. This paper investigates the impact that climate change over the last two decades may have on the design and performance of buildings by examining the specific impact that changes in temperature and solar radiation have had on one particular design variable, energy use. Impact of climate change on the building materials can lead to the loss of strength, color. The results indicate that the temperature and solar radiation in India have changed significantly in the last 15 years and that the climatic data currently being used for energy design calculations leads to inaccuracies in predictions of energy use. It is concluded that the climatic data used in these calculations should be urgently reviewed as it may be leading designers to adopt solutions which will be inappropriate for future use.