UPDATE 2-Mexico Sept consumer confidence falls to 9-month low

* Adjusted confidence falls to 93.4 in Sept vs 94.8 in Aug

* Spike in inflation, signs of slower growth weigh on sentiment

MEXICO CITY Oct 4 (Reuters) - Mexican consumer confidence fell to its lowest in nine months in September, dipping for the second straight month as inflation climbed to a 2-1/2-year high and the economy showed signs of slowing.

The seasonally adjusted index fell to 93.4 in September compared to a downwardly revised 94.8 in August, according to data from the national statistics agency.

The September index was the lowest since December 2011 and followed a drop in August as well.

Consumers' willingness to make major durable goods purchases contracted, likely dented by the spike in inflation to 4.73 percent in early September, while signs of slowing growth hit the outlook on the economy over the next year.

"These two months of contraction are worrying," said Alejandro Cervantes, an analyst at Banorte-IXE in Mexico City. "Consumers could be expecting that the rhythm of growth in the Mexican economy will slow in the coming months."

The unadjusted index fell to 94.0 in September, its lowest since March 2012, and was down compared to 97.6 in August.

A slowdown in the United States is expected to drag on the economy of Mexico, which sends nearly 80 percent of its exports to its northern neighbor.

Still, analysts see the Mexican economy expanding 3.85 percent this year, according to a central bank poll on Monday, cooling from a more than 4 percent rate in the first half of the year.

With risks to both inflation and growth, investors are betting that policymakers will hold Mexico's benchmark interest rate steady at 4.50 percent through next year..

"Given the current level of inflation, it is improbable that the Banco de Mexico is motivated to lower interest rates, or to raise them with a slower pace of growth," Cervantes said.

Mexico's jobless rate rose in August, breaking a five-month streak of declines, while a survey this week showed the pace of growth in the manufacturing sector slowed for the third month in a row in September.