With cooler weather has come a cooler economy in Utah, according to a business-conditions gauge produced by Creighton University in Nebraska.

The Utah Business Conditions Index, based on a survey of supply managers and business leaders, slipped to 63.8 in September from August's 71.8.

The index has a range from zero to 100. A figure higher than 50 indicates an expansionary economy over the next three to six months. It uses the same methodology as the Institute for Supply Management's membership survey.

Components of the overall Utah index for September were new orders at 75.0, production at 50.0, delivery lead time at 74.3, inventories at 72.3 and employment at 52.3.

"Durable and nondurable manufacturers in Utah reported strong activity for the month," Ernie Goss, director of Creighton's Economic Forecasting Group and an economics professor, said in a prepared statement. "Economic growth has meant strong business growth for the state's trucking industry."

The September figure is in contrast to January's 86.8 — the highest index for 2007 — and down from 73.6 in July and 71.8 in August.

Meanwhile, the Institute for Supply Management said Monday that its manufacturing index for the country registered 52.0 in September, down from 52.9 in August. It was the lowest reading since the gauge was at 50.9 last March. Analysts had expected a reading of at least 52.5.

Creighton's Mountain States region index was 64.8 in September, down from 77.7 in August and 71.4 in July. It includes Utah, Colorado and Wyoming.

"While the national economy continues to weaken, the Mountain States region is growing at a brisk pace. Results from our survey point to robust growth in the months ahead," Goss said.

He noted that the "economic optimism" component fell to a still-high 60.0 from 67.9 in August and 78.6 in July.

"The August credit crisis and the downturn in the housing sector pushed the confidence index down for the month. It is clear national issues are having some effect on the outlook of supply managers even as the region experiences vigorous growth," he said.

As for job growth, he is predicting an annualized increase for the fourth quarter to top 2 percent in the region while the national figure would be less than 1 percent.

Colorado's overall index was 66.7 in September, down from 80.7 in August. Wyoming's fell to 64.0 from August's 76.2.