The national average price was $3.27, which is 1.5 percent less expensive than the same time last month and 6.8 percent less year-on-year, the automobile association said.
The AAA's monthly gasoline price report published Thursday said prices declined in January because extreme winter weather kept demand low.
AAA spokesman Avery Ash said gasoline prices typically increase in February as oil refineries start regular maintenance.
An increase this year may be tempered by the harsh winter.
In November, the AAA said about 25 percent of the retail filling stations in the United States were selling gasoline for less than $3 per gallon.