American industrial production managed only a meager gain in August as summer coolness held back utilities, but manufacturing output rose a second month in a row.

Industrial production increased 0.1% last month, after rising an upwardly revised 0.6% in July, the Federal Reserve said yesterday. August industrial capacity utilization at 77.3%, was unchanged from July’s revised level, which was originally reported at 77.1%.

The paltry production increase came in short of what Wall Street expected. The median estimate of 21 economists surveyed by Dow Jones Newswires and CNBC had called for overall output to rise 0.5% and for capacity use to notch up 0.3 percentage points to 77.4%.

But the president of ClearView Economics in Pepper Pike, Ohio, Ken Mayland, said the slight increase in total production diverts attention from the gain in manufacturing.

“While the overall increase seems anemic, the fact is a cool summer and declining output in utilities retarded that overall advance and obscure the fact manufacturing output rose,” Mr. Mayland said.

The Fed data show utilities production tumbled 2.4% amid cool weather in many parts of the country. Utilities fell 2.0% in July and 1.8% in June.

Mr. Mayland pointed out declining utility output was good, in a way, because the cool-weather factor lowered air-conditioning bills around a time of higher prices at the gasoline pump.

Output in the mining industry dropped 1.1% in August after rising 1.3% in July and dipping 0.9% in June.

Manufacturing climbed 0.5%, after rising 0.9% in July and sliding 0.2% in June. Manufacturing originally was seen going up 0.6% in July.

“Looking at these numbers, you can’t conclude anything but that manufacturing is soaring,” Mr. Mayland said.

A separate report showed manufacturing activity in the New York Federal Reserve district rebounded to a reading of 28.34 in September from an upwardly revised 13.22 in August. It was the 17th straight month of positive readings.

And a report by the Commerce Department showed business inventories climbed more than sales during July.

Inventories rose 0.9% to a seasonally adjusted $1.247 trillion, after a revised 1.1% advance in June. The two months of increases were the strongest twin advances since late 1999, when inventories rose 1.1% in November and 0.9% in December of that year, Commerce said.

Business sales rose 0.6% in July, after increasing a revised 0.2% the previous month.

Retail inventories advanced 0.6% in July, boosted by a 1.8% increase in automobile stockpiles. Excluding autos, retail inventories would have been flat.

A Lehman Brothers economist, Drew Matus, said the increase in overall inventories, a shade higher than what analysts were expecting, indicates companies are replenishing to meet higher anticipated demand.

“There’s really nothing to suggest there is an unwanted inventory buildup outside of the auto sector,” Mr. Matus said.

UBS economist James O’Sullivan pointed to an “exceptionally low” inventory-to-sales ratio of 1.32. The ratio, an indicator of how well firms are matching supply with demand, measures how long it would take in months for a firm to sell its current inventory.

“There’s a little excess in autos, but outside of that, inventories seem to be pretty lean,” Mr. O’Sullivan said.

He said surging spending late last year caught some companies by surprise.

“I think some of this may be a voluntary rebuild,” Mr. O’Sullivan said. “The inventory-to-sales ratio probably got a little too low.”