The present work attempts to provide more accurate estimate of HDD and CDD and investigates the suitability of high resolution downscaled seasonal climatic forecasting models for assessing and accurately estimating the energy demands of buildings. The analysis has been established through a series of indices for estimating heating (HDD) and cooling degree days (CDD) using interpolated hourly data which were produced from the model output. The work has considerable potential to provide refined inputs for assessing building sector-specific vulnerability to climate change: energy supply and demand. In this work the application of the above mentioned methodological approach in the assessment of the energy performance and requirements of buildings on Greece are presented, for a period and with a forecast horizon of 6 months. The ARW-WRF model has been set up and validated to produce downscaled climatological fields for Greece, forced by the output of the CFSv2 model, with a horizontal spatial resolution of 5km×5km. The data, that covered all Greek regions and climatology zones according to the existing building regulations code and the region elevation present a very reasonable correlation with data published in previous studies.