Why OPEC's Success Hinges on a Change of Seasons

Global oil consumption ebbs and flows from one season to the next. So the current months of higher demand will be scrutinized closely for signs of whether production cuts from the Organization of Petroleum Exporting Countries and its allies are bearing fruit. The group is struggling to clear the glut that’s kept prices close to $50 a barrel -- half the level three years ago. The annual rhythms of refiners, U.S. motorists and the weather will play a big part in determining whether the cartel’s effort to boost prices is successful.

Demand for oil tends to increase during the summer as U.S. households hit the road for their vacations. Consumption tails off in September as the driving season ends and refineries halt for maintenance, before rising again at the start of winter as people burn oil for heating. Periods of higher demand offer OPEC an opportunity to make a significant dent in swollen crude stockpiles, while the lulls carry the risk that the surplus will grow again.