In this paper, hourly based weather data from 1991 to 2000 of three major cities in Vietnam; i.e., Hanoi, Danang, and Cantho, are prepared for the purpose of using in the building thermal environment simulation and energy consumption calculations. The data sources are the weather data compiled by the Meteorology and Hydrology Department of Vietnam. Since the missing data in the data sources are very few, they can be easily filled in most cases with linear interpolation. The prepared weather parameters are temperature, relative humidity, wind speed, wind direction, precipitation amount, sunshine duration, cloud amount, solar irradiation and downward atmospheric irradiation. The reference years are also prepared by selecting the typical months from the 10 year data according to the three methods; i.e., SHASE, EA-DMV and EA-DWT methods.