No play was possible in Hobart, where the Aussies had been bowled out for 85 on day one, before South Africa reached 171-5 in reply.
Temba Bavuma (38) and Quinton de Kock (28) are the not-out batsmen.
Play will now begin 30 minutes early at 10am local time (23:00 GMT) on the three remaining days of the game.
South Africa were denied the chance to press home their advantage over Australia when rain washed out the second day of the second Test.