Adelaide is bracing for a blast of extremely hot weather with forecast temperatures set to soar into the low 40s.
The Bureau of Meteorology has forecast a top temperature of 41 degrees on Thursday and 42 on Friday.
A milder change will bring some relief over the weekend before the mercury tops 40 degrees again on Monday and Tuesday.
The hot conditions have prompted warnings from both SA Health and SafeWork SA, urging people to avoid heat stress.
Director of public health Kevin Buckett said it was important for people to stay well hydrated during prolonged periods of hot weather.
"If you do need to go into the sun, do so for limited periods and wear a long-sleeved, light coloured shirt, a hat, sunglasses and plenty of sunscreen," he said.
"Try to make the most of fans and air-conditioners, or if that is not an option, you can cool down by placing wet towels on your neck and underarms or by having a cold shower or bath."
Dr Buckett said the elderly, babies and young children were most at risk from heat-related conditions.
Symptoms of heat exhaustion include nausea, faintness and dizziness, loss of appetite, weakness, headaches, vomiting, lack of sweating and reduced urine output.
SafeWork SA said workplaces should ensure they had measures in place to cope with the heat.
"Hot weather is a hazard that needs to be considered when planning work activities," acting executive director Robin Scott said.
"Heat stress can afflict workers at outdoor locations such as construction sites, storage yards, roads and farms.
"It is also important to recognise that heat poses a risk in confined spaces. Temperatures in industrial sheds can exceed 50 degrees, placing workers at risk."