Adelaide has wettest July day for decades

South Australia faced snow as well as heavy rain on Tuesday.

Bureau of Meteorology spokesman Paul Lainio said in the 24 hours to 9am, Adelaide had 37mm of rain while falls of more than 50mm were recorded in the Adelaide Hills and south of the city.

A cold snap also brought a light dusting of snow on Mt Lofty early on Tuesday morning as temperatures plunged.

"It was a quite an unusual system to develop so quickly and be so intense in such a short period of time," he said.

Strong winds also pushed rain further north than expected with gusts of more than 90km/h recorded in Adelaide and in some regional centres.

The State Emergency Service said the winds and rain caused widespread damage, bringing down trees.

The SES responded to more than 300 calls for help, most for water entering homes.