U.S. refinery issues and recovery for oil prices means retail gasoline prices are closing in on their highest levels since December, market analysis finds.

Motor club AAA reports a national average retail price for a gallon of regular unleaded gasoline at $1.98 per gallon for Tuesday, steady from the previous day but 4 cents higher than last week and 27 cents, or 16 percent, higher than one month ago.

According to AAA, it's the second straight week for increases in prices at the pump. The motor club said the onset of spring coincides with a period when refineries are conducting maintenance as they ready to prepare a summer blend of gasoline, which because of additional environmental safeguards is more expensive to make.

"These factors typically lead to higher gas prices this time of year and have helped push prices higher in recent weeks," the motor club said in a weekly retail market report.

Regionally, Exxon Mobile's refinery in Torrance, Calif., suffered a power outage and is offline in terms of gasoline production. The refinery produces about 10 percent of California's gasoline and already has been operating at a lowered capacity for more than a year.

Retail price watchdog GasBuddy said in a separate emailed report the price increases for gasoline have moved slower than expected, though it forecasts the average retail price for gas will soon break through the $2 per gallon mark.

Crude oil prices, which account for the bulk of the price at the pump, have leveled out at around $40 per barrel after twice dipping below $30 per barrel in early 2016. Positive pressure could emerge for oil prices as major oil-producing states meet in April in Doha to consider a freeze to output levels.

New Jersey has the lowest state average price in the nation at $1.73 per gallon.