HOUSTON, Nov. 21 (Xinhua) -- U.S. average gasoline prices at this Thanksgiving holiday reach a three-year high, the U.S. Energy Information Administration (EIA) said on Wednesday.

Heading into the Thanksgiving holiday weekend, U.S. retail regular-grade gasoline averaged 2.61 U.S. dollars per gallon, up 4 cents per gallon from the same time last year. This year also marks the highest gasoline price for the Monday before the Thanksgiving holiday weekend since 2014.

Retail gasoline prices have increased steadily from January through May in 2018. Prices started at 2.52 dollars per gallon on Jan. 1 and peaked at 2.96 dollars per gallon on May 28, according to EIA's weekly report on gasoline and diesel fuel.

From June to October in 2018, retail gasoline prices steady between 2.85 dollars per gallon and 2.90 dollars per gallon.

Recently, retail gasoline prices have fallen slightly, partly because of seasonal factors. Gasoline prices are often higher in summer months when gasoline demand is higher and when federal and state environmental regulations require the use of summer-grade gasoline, which is more expensive to manufacture.

Gasoline prices continue to be closely linked to crude oil prices. The spot price for the key global crude oil benchmark Brent was 64.14 dollars per barrel as of Nov. 19, about 3 dollars per barrel higher than the price from the same time last year.

The Brent crude oil spot price has recently decreased from a weekly average of 85.44 dollars for the week ending on Oct. 5 to a weekly average of 70.34 dollars for the week ending on Nov. 9.

The decrease in Brent crude oil prices, combined with other factors, has contributed to a more than 20-cent-per-gallon fall in the U.S. average retail gasoline price since the week of Oct. 8 this year, according to the EIA.