Residents of South Africa's north-eastern provinces have been warned to brace themselves for a second heatwave that is expected to hit the area on Thursday. Gauteng, Limpopo, Mpumalanga, the Free State and the North West will experience heatwave conditions until at least Monday, the South African Weather Service (SAWS) has warned. This is the second heatwave to hit those provinces in the space of a week. In the first, temperatures in some places soared to 38°C.According to the SAWS, a heatwave with persistently high temperatures is expected over the eastern parts of the North West and the Free State from Thursday, the Lowveld of Mpumalanga and Limpopo from Friday, and the entire provinces of Limpopo, Mpumalanga and Gauteng from Saturday - continuing until at least Monday. "Hot and humid weather will result in extremely uncomfortable conditions over the Lowveld of Mpumalanga and Limpopo from Friday, spreading across the provinces on Saturday and continuing until at least Monday," the SAWS said. The SAWS said people should stay indoors in a cool room near a fan, if possible. "The old and infirm must take extra care to stay hydrated and cool. Avoid strenuous outdoor activity, playing excessive sport and hard labour. Dress in lightweight clothes and drink plenty of liquids - not alcohol. Ensure that pets and livestock have enough access to water," the SAWS advised. SAWS forecaster Edward Engelbrecht earlier told News24 that a heatwave occurs when temperatures are 5°C higher than the average temperature of the warmest month – which is January – for three consecutive days.