The Country Fire Service says northwest pastoral and the west coast have been rated at severe for Tuesday.
It says very hazardous fire weather conditions are forecast and locals are advised to activate their bushfire survival plans.
The Bureau of Meteorology says the temperature will hit 34C in Adelaide on Tuesday and will go as high as 43C in some regional centres.
On Wednesday conditions will get even hotter with Adelaide tipped to have 38C and Coober Pedy, in the state’s north, to have 45C.
Meanwhile, a man has been accused of lighting a series of grass fires in Adelaide.
The 38-year-old allegedly lit three grass fires in Hallett Cove in Adelaide’s southern suburbs early on Tuesday morning, police say.
The man was refused bail to appear in Adelaide Magistrates Court on Tuesday charged with arson.
Make your contribution to independent news
A donation of any size to InDaily goes directly to helping our journalists uncover the facts. South Australia needs more than one voice to guide it forward, and we’d truly appreciate your contribution. Please click below to donate to InDaily.