Average gas prices in North Carolina increased by 15 cents in the past month—the highest rate since July 27, 2013, according to AAA Carolinas.

Now sitting at $3.53 per gallon as of April 8, gas prices are up from a month ago, when the price was $3.38.

After starting 2014 at $3.31 on Jan. 1, gas prices fell to a year-low of $3.28 on Feb. 8 before beginning an upward increase.

Prices typically tend to rise in the spring due to refinery maintenance, according to AAA. The tightened supply across the country results in higher gas prices. Refineries must also make the switch to summer fuel blends by May 1.

Gas prices are expected to continue to rise until refinery maintenance is completed, which is likely to be by the end of April.

Another factor that contributes to higher prices is an increase in gasoline demand due to warmer weather and the beginning of vacation-travel season.

Although demand will continue to climb as the beginning of summer nears, an increase in gasoline production will allow supply levels to keep up with that demand.

And good news for drivers, AAA Carolinas predicts that overall, gas prices for 2014 will be slightly cheaper than 2013.