Gas prices climb for 21st day

Changing gas prices is becoming a daily occurrence, with the national average approaching $3.72 a gallon.

NEW YORK (CNNMoney) -- Gas prices continued to climb on Tuesday, inching closer to $4 a gallon as they rose for the 21st day in a row.

The nationwide average rose to $3.72 a gallon, up 2 cents from a day earlier, according to the motorist group AAA.

Only a month ago, the nationwide average was $3.42 a gallon.

Gas prices are up 13.3% so far in 2012. The average price is down 40 cents, or about 9.7%, from the record high of $4.11 reported on July 17, 2008.

Average prices for regular gasoline are more than $4 a gallon in California, Alaska and Hawaii. Gas prices are just shy of the $4 mark in New York, Connecticut, and Washington, D.C., according to AAA. The lowest average gas prices are in Wyoming and Colorado, where a gallon is going for less than $3.20.

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Gas prices have been rising on the back of soaring oil prices, which have surged 10% over the past month amid fears that tensions with Iran will lead to an all-out war that causes a disruption in oil supplies.

Signs of an improving economy have also been boosting oil prices, along with the stock market, which has seen the S&P 500 (SPX) rise by more than 8% in 2012.

On Monday, TransCanada (TRP) announced that it will move forward with parts of the Keystone XL pipeline, which will boost the flow of crude oil from the oil sands of Canada to the Gulf Coast. While the White House denied a more controversial proposal earlier this year, this portion does not require federal approval and is expected to be operational in 2013.

As gas prices soar, Republican candidates are looking to tie Obama's policies to the increase.

On Monday, Rick Santorum blamed the president for blocking the expansion of domestic energy production. Santorum also argued that high gas prices were to blame for the 2008 housing meltdown and ensuing economic slump.