Urban influences on South African temperature trends

Temperature trends are examined for a variety of locations in South Africa. The long-term mean annual temperature record (1885-1993) shows warming over the past century, with much of the warming occurring in the most recent three decades. However, our analyses show that half or more of this recent warming may be related to urban growth, and not to any widespread regional temperature increase. Maximum and minimum temperatures for the period 1960-1990 reveal a statistically significant decrease in the diurnal temperature range in large urban areas, but no change in the non-urban network. This assessment of the urban effects on temperature trends in South Africa may contribute to our understanding of apparent climate changes occurring in the Southern Hemisphere during the period of historical records.