South Africa is experiencing increasingly longer summers and shorter winters, climate change specialists have found. This was revealed in a new study conducted by Adriaan van der Walt, lecturer in the Geography department at the University of the Free State (UFS) and his counterpart at Wits University, Jennifer Fitchet. In the study, data on daily maximum and minimum temperatures was collected from 35 meteorological stations of the South African Weather Service, covering the period between 1980 and 2015.
Gone were the days when South Africans experienced a three-month spring season, easing into summer, and then cooling off for three months before hitting winter. Their statistical seasonal brackets indicate that South Africans currently experienced longer summers (from October to March), autumn in April and May, winter from June to August, and spring in September.
A first for South Africa, temperature was used in this study rather than rainfall as a metric to determine seasonal change. South Africa had consistent enough temperature fluctuations, unlike in many other countries, for this to be possible.
Although considerable work had been done using rainfall to determine seasonality in Southern Africa, Van der Walt found that these methods were less efficient as there were too many inconsistencies in this approach (2019, South African Geographical Journal). To make matters more complicated, some regions do not have enough rainfall to use as a classifier. It was, after all, a semi-arid region, with desert conditions along the west coast.
According to Van der Walt, they believe that a clearly defined and communicated method should be used in defining seasons, rather than just assigning months to seasons. “One of the most important arguments of our work is that one needs to critically consider breaks in seasons, rather than arbitrarily placing months into seasons, and so we welcome any alternate approaches,” he said
A number of sectors apply the temperature-based division to their benefit. “For example, in the tourism sector it is becoming increasingly important to align advertising with the season most climatically suitable for tourism,” says Van der Walt.