Heat relief for Adelaide's rough sleepers

A new initiative will help people sleeping rough in the heart of Adelaide to find some relief from the heat during a sweltering Christmas period, the state government says.

The "Code Red" response will mean some homelessness services will be open longer and food, water, hats and sunscreen will be available to those doing it tough in the CBD from Friday.

The response, a twist on the "Code Blue" that aims to shield the homeless from extreme winter weather, will be rolled out statewide early in 2017 if successful.

Adelaide is forecast to reach 37C on Friday, 37C on Christmas Eve and a scorching 40C on Christmas day before a stormy change rolls through on Boxing Day.