We present the energy use situation in Hong Kong from 1979 to 2006. The primary energy requirement (PER) nearly tripled during the 28-year period, rising from 195,405 to 566,685TJ, about two-third of which was used for electricity generation. The residential and commercial sectors are the two largest electricity end-users with an average annual growth rate of 5.9% and 7.4%, respectively. The monthly consumption in these two sectors shows distinct seasonal variations mainly due to changes in the air-conditioning requirements, which are affected by the prevailing weather conditions. Principal component analysis of five major climatic variables-dry-bulb temperature, wet-bulb temperature, global solar radiation, clearness index and wind speed-was conducted. Measured sector-wide electricity consumption was correlated with the corresponding two principal components determined using multiple regression technique. The regression models could give a very good indication of the annual electricity use (largely within a few percents), but individual monthly estimation could differ by up to 24%. It was also found that the climatic indicators determined appeared to show a slight increasing trend during the 28-year period indicating a subtle, but gradual change of climatic conditions that might affect future airconditioning requirements. (C) 2007 Elsevier Ltd. All rights reserved.