A market return by U.S. holiday-goers and anticipation over OPEC's meeting at the end of the week pushed crude oil prices higher on the last day of November.

Monday marked the return to regular trading after the long U.S. holiday weekend. West Texas Intermediate, the U.S. benchmark price for crude oil, rose 1.6 percent in early trading to $42.31 per barrel. Brent rose 1.4 percent to $45.50 per barrel.

After a quiet start to the holiday shopping season, investors are watching closely for signs of momentum moving into 2016. The European Central Bank is expected to review potential stimulus measures and U.S. Federal Reserve Chairwoman Janet Yellen unveils her outlook on the U.S. economy Thursday.

ECB President Mario Draghi in October said the regional economy was showing signs of resiliency, but risks remained on the horizon. Yellen, for her part, testified earlier this month on Capitol Hill, signaling there may be an interest rate increase announced in December, though it would be a slow implementation.

There are signs for improvement in the U.S. economy, she said, but more work remains to be done and the work of the Federal Reserve "is not complete."

Market fundamentals still show a heavy tilt toward the supply side as economic growth is not enough to take up the excess of crude oil on the market. Iran during the weekend showcased the potential for investments in a post-sanctions climate and, on Monday, Swiss energy company Lundin Petroleum started new commercial oil production in the North Sea.

Members of the Organization of Petroleum Exporting Countries are expected to welcome Indonesia back into the group during its regular meeting Friday. De facto leader Saudi Arabia has said more production is needed to satisfy expected demand from Asia and, while Iran is re-emerging as a major supplier, no major changes are expected from OPEC ministers later this week.

Oil prices are down about 10 percent for November.