GRAND RAPIDS, Mich. (WOOD) — Drivers in Michigan keep seeing an increase in gas prices.

Currently, it costs an average of $3.37 a gallon to fill a tank. That’s almost 40 cents higher than what it was last month.

Patrick De Haan, the head of petroleum analysis at GasBuddy, said the arctic blast has limited refinery output and China’s economy reopening is driving demand. He added that releases from the nation’s petroleum reserves are over and there is a lot of oil going into the market.

He said the EU plans to sanction Russia on Feb. 5, which could lead to tightness in the market.

“As we move toward spring, refineries are also starting to do maintenance here in the weeks ahead. And then the transition to summer gasoline. All of these ingredients pushing up gas prices,” said De Haan.

De Haan believes $4 a gallon gas is a possibility but hopes it holds off until March or April. Looking ahead, he said he hopes we don’t see $5 a gallon gas this summer.

Currently, he said wholesale clubs are holding on to the lowest prices in the Grand Rapids market. He warned not to be surprised to see another hike next week. Wholesale prices for gasoline are now up 70 cents a gallon since just before Christmas.

“While gas prices have gone up for four straight weeks, diesel prices have only gone up for the last week,” he said.

While the jump in gas prices has been about 12 cents compared to a week ago, diesel is only up a couple cents a gallon. De Haan is hopeful that by spring, diesel prices will not be as high as they are now.

De Haan urged drivers to pass on $3.45 per gallon gas right now, because he thinks it will go down in the next couple of days. He said if you see $3.15 a gallon, it’s best to fill up because those prices are likely to go up.