Abstract:
Previous assessments of historical trends of measured surface temperature in South Africa have all
shown a general upward trend, in both mean and extreme values, over recent decades. In addition,
some regional differences in trends have been identified. Most of these studies focused on the period
from about 1961 up to the last year that could be included before publication, as only climate stations
situated in the same position for the entire analysis period were analysed. A data homogenisation
procedure enabled the combination of time series of stations from which trend analysis could be
applied, extending the common analysis period for this study back to around 1931. The trend results,
based on the WMO ETCCDI indices, continue to show the general warming trend shown in previous
analyses, with a general increase in extreme warm events, and a general decrease in extreme cold
events across South Africa. The analysis of seasonal trends show that, while there are noteworthy
differences on a regional basis, austral summer shows on average the strongest warming, followed by
autumn, winter and spring. The central interior, which exhibited significant cooling in previous
analyses, now shows non-significant or similar trends when compared to the other parts of South
Africa. There is no countrywide acceleration in the warming trends, but some regional consistencies
in the temporal changes in trends could be determined, i.e. increases in trends in the central interior
and decreases in trends along most of the coastal region.
