(Bloomberg) -- Gasoline prices have surged to a record high for this time of year in the US, jeopardizing the fight against inflation that’s dogged President Joe Biden. Most Read from BloombergAverage regular gasoline now costs $3.866 a gallon, a seasonal record on a trailing-12-months basis, according to data from the American Automobile Association. Gasoline costs already accounted for over half of the increase in the August consumer price index. Biden last year released a record amount of emergency oil supply in order to tame gasoline’s record summertime surge. Compounding higher gasoline prices is a simultaneous spike in diesel costs.