We used 1954-1983 surface temperature from 42 Chinese urban (average population 1.7*106) and rural (average population 1.5*105) station pairs to study the urban heat island effects. Despite the fact that the rural stations are not true rural stations, the magnitude of the heat islands was calculated to average 0.23 ¿C over the thirty-year period with a minimum value during the 1964-1973 decade and maximum during the most recent decade. The urban heat islands were found to have seasonal dependence with the Northern Plains dominating the magnitude of the heat islands. The changes in heat island intensity over three decades studied suggest a general increase in heat island intensity of about 0.1 ¿C, but this has not been constant in time. These results suggest that caution must be exercised when attributing causes to observed trends when stations are located in the vicinity of metropolitan areas. ¿American Geophysical Union 1990