Chicago Fed Sept national activity index weakens

NEW YORK Oct 26 (Reuters) - U.S. economic activity weakened in September according to a Chicago Federal Reserve report on Monday, but a three-month moving average of the index, though below its historical trend, improved close to levels associated with the end of recessions.

The Chicago Fed said its National Activity Index weakened to minus 0.81 in September from a revised minus 0.65 in August, previously reported at minus 0.90.

Zero values in the index indicate a national economy expanding at historical trends, while negative values indicate below-trend growth and positive values signal growth above trend, the Chicago Fed said.

The three-month moving average, which smooths out monthly volatility, firmed to minus 0.63 in September from August's revised figure of minus 0.96, previously reported at minus 1.09. The Chicago Fed said that in the past four recessions, the three-month average's rise back above minus 0.70 has coincided closely with the end of the recession.

Thirty two of the 85 individual indicators in the index made positive contributions to the index in September.

(Reporting by John Parry; Editing by Chizu Nomiyama)