WASHINGTON — U.S. consumer confidence fell this month to the lowest level since September. Consumers are worried about the job market and rattled by events in Greece and China.

The Conference Board said Tuesday that its index of consumer confidence fell to 90.9 in July from a revised 99.8 in June. That’s the lowest since September’s reading of 89. Consumers’ assessment of current conditions fell slightly to a still-healthy 107.4 from 110.3 in June; but their outlook for the next six months dropped sharply to 79.9 this month, the lowest since February 2014 and down from 92.8 in June.

Lynn Franco, a Conference Board economist, says consumers may have been concerned about the debt standoff in Greece and a stock market plunge in China.

The percentage of consumers describing current business conditions as “good” slipped to 24.2 percent from 26.1 percent in June. The percentage expecting the job market to improve over the next six months dropped to 13.1 percent from 17.1 percent in June; the percentage expecting fewer jobs in six months rose to 20 percent from 15.2 percent.

Consumers were also slightly less likely to expect their incomes to grow in the next few months and more likely to expect them to fall.

Adam Collins, an economist with Capital Economics, said the dip in confidence also reflects higher gasoline prices in recent months; prices hit bottom at $2.03 a gallon in late January and have since rebounded to $2.70 a gallon, according to AAA. Consumer caution may reduce spending to an annual growth rate of 2 percent in the July-September period from the 2.7 percent forecast for the April-June period, Collins said in a research note.

He predicted their mood will improve. “With the labor market likely to strengthen further, wage growth poised to accelerate and the recent fall in oil prices suggesting gasoline prices may start to decline again,” he wrote, “confidence should rebound soon.” He expects consumption growth should then rise back toward 3 percent.

Still, Mark Vitner, senior economist at Wells Fargo Securities, worries that consumers’ darkening mood reflects bigger problems. A strong dollar has made U.S. products less competitive in foreign markets, hurting American manufacturers. And weakening global economic growth has pushed down commodity prices and hurt mining and energy firms.