Other cities across the South and Southwest saw double-digit increases in consumer prices, with the Atlanta metropolitan area posting annual inflation of 11.7% and Miami reaching 10.7%, according to Bureau of Labor Statistics data.

Overall inflation was resurgent in August, dashing hopes of a nascent slowdown even as gasoline prices declined. But the national average of 8.3% masks growing disparities among cities, making the Federal Reserve's fight against inflation more complicated.

In San Francisco, consumer prices rose 5.7% in the 12 months through August, while in Los Angeles the rate was 7.6%. In the New York city metro area, prices rose 6.6%, a slight acceleration from 6.5% in July.

Meanwhile, high housing costs are dogging the Sun Belt, where a shortage of apartments and houses and an inflow of investors have been driving up rents. Shelter costs in metropolitan Phoenix climbed 19% in August from the previous year, compared with a 6.2% gain nationwide.

The price surge in Phoenix and Atlanta, Arizona and Georgia's biggest cities, respectively, coincide with two contested US Senate races at the midterm elections in about eight weeks.