The Commerce Department report said the number is an increase over 666,000 new sales for July. The median sales price was $328,400 while the average price was $404,200.
The department said the seasonally-adjusted estimate of a new house for sale by the end of August was 326,000, projecting a supply of 5.5 months.
RDQ Economics said Wednesday the numbers showed buyers are gravitating toward lower mortgage rates.
"We expect residential investment will add to third-quarter real (gross domestic product) growth following six consecutive quarterly contractions," the firm said in a client note.
The 713,000 figure marked the second-largest sales month of the year, behind the 729,000 in June. The South recorded the most sales, at 426,000. The West saw the second-most, with 191,000.
