Abstract
From 1960 to 1990, reading of meteorographic paper and other manual work were required to draw up hourly weather data in Tokyo. Since 1991, SDP (Surface Daily Data Observation Point) data gathered by the Meteorological Agency have made it easy to obtain those weather data every hour. Based on the 40-year-long weather data, outdoor design conditions for cooling and heating in every decade between 1960 and 1999 were set. Regarding fluctuations in temperature under those conditions, the daytime highest temperature has not changed much during that period, while the lowest temperature has risen decade by decade. The intensity of solar radiation has increased slightly. Due to small changes in absolute humidity despite increases in temperature, relative humidity has fallen, causing air to become dry. The outcome of the calculation of cooling and heating load during that period shows that annual cooling load has been on the rise year by year, but that the margin of decrease in heating load has been widening.
