Severe bushfire conditions in SA

Severe bushfire conditions have been declared in five South Australian districts as the state swelters through a December heatwave.

The Country Fire Service says conditions will be severe in the Flinders, Mid North, Mount Lofty Ranges, Riverland and Murraylands districts on Friday.

Adelaide and many South Australian regional centres are set to post four consecutive days above 40C this week, the first time that has happened in December.

But light winds have so far reduced the fire risk.