The price per gallon for regular unleaded gasoline has increased 29 days in a row as of Tuesday because of U.S. refinery issues and commodity markets, AAA said.

AAA reports an average national retail price for a gallon of gasoline at $2.31, up about a penny from Monday and 28 cents from one month ago. Gasoline prices dropped steadily during the latter half of 2014 as oil prices traded in a bear market, though it was Jan. 26 last time prices at the pump fell.

The motor club said in a Monday report that some of the increase is tied to seasonal maintenance at U.S. refineries, which limits fuel production and crimps supplies. Refineries in late winter start making preparations to produce a summer blend of gasoline, which is more expensive to make because of additional steps needed to prevent vaporization in warmer months.

"There remains the potential for unexpected refinery problems to further impact production and cause temporary price spikes in various regions," the report stated. "Last week an explosion at the Exxon Mobil refinery in Torrance helped push up prices in California, while bitterly cold weather in the Northeast and Midwest led to a number of refinery problems in those areas."

The motor club said crude oil prices are rising, but still below historic averages, which should moderate any major swings in gasoline prices. Consumers are still saving about $1.11 per gallon year-on-year, but prices are expected to rise in the midterm.

"Ample domestic supply is expected to keep a ceiling on prices, though there is a good chance that prices will continue to rise this spring," AAA said.

Two states are posting an average price below the $2 per gallon mark: Idaho at $1.96 and Utah at $1.95. The national average price on this date in 2014 was $3.42.