AAA's Monday morning numbers put the average price of gas in Michigan at $2.23. Monday afternoon, though, you'll see $2.43 all over Lansing. Gas watchers say it jumped more than 20 cents overnight.
Representatives for the oil companies at the American Petroleum Institute blames it on record crude oil prices. That theory means they could remain high all summer long.
The president of the SSDA, Service Station Dealers Association, says it could be a springtime regularity. Ed Weglarz says a gurgle of gas and a sigh of frustration have been the sounds of springtime for two decades.
"19 of the last 20 April's we've seen a price spike of about 15 or 30 cents and they've attributed it to the changeover from winter to summer gas," Weglarz says.
It's just one of his theories, but he says that could help explain what he calls the biggest spike since the Wolverine gas line break in mid-Michigan in 2000.
The "summer gas" theory postulates gas supply is low this month while refineries swap production to a gas that vaporizes more slowly. It's an enviromental regulation from the government that they make the switch by May 1. It means this high could be temporary.