CHICAGO (CBS) — For the first time this year, the average price of gas in the Chicago area has climbed to more than $3 per gallon.

Prices jumped by an average of 8 cents a gallon overnight, with some stations jacking up prices 25 cents per gallon.

The average price of a gallon of regular unleaded stood at $3.04 as of Wednesday morning, about 27 cents higher than a month ago.

“A lot of stations, now, closer to downtown well over $3 a gallon; as folks obviously hitting the road for Memorial Day,” said Patrick DeHaan, senior petroleum analyst at GasBuddy.com.

DeHan said the recent spike comes even as crude oil prices have been trending lower. He blamed rising prices on weekend problems at the ExxonMobil refinery in Joliet.

“Unfortunately, because of that refinery outage, and the unique type of gasoline that we use in Chicago, there’s a little bit of a tight market, and that’s playing into why gas prices are going up,” he said. “The good news is that it will be temporary. Hopefully, once that refinery gets back on its feet in, say, another week or two, prices should contract again.”

Chicago area gas prices also are still about 90 cents lower than this time last year.