Gasoline prices in Denver averaged $3.40 a gallon last week for the third straight week, 31.3 cents a gallon cheaper than the same period a year ago.

The cost of gasoline in Denver was 23 cents cheaper than the average cost of a gallon of gasoline nationally which stood at $3.63 a gallon on Sunday, according to GasBuddy.com.

The national average fell 0.9 cents a gallon in the last week.

The national average has increased 0.3 cents a gallon during the last month and stands 0.4 cents a gallon lower than this day one year ago.

The lower gasoline prices in Denver follow the trend predicted by analysts early in the year. Gasoline costs in Denver are usually far below the national average.

GasBuddy said there was relatively little movement in gasoline prices across the nation.

Patrick DeHaan, senior petroleum analyst for GasBuddy.com, said he couldn’t recall a time when the national average has remained so steady.

“If you’re a motorist, I’m not sure if seeing such duplicity is bad since prices have remained…relatively clam,” DeHaan said in a statement.

DeHaan said, however, he is now beginning to doubt any major summer decline in prices similar to the past few years.

GasBuddy operates DenverGasPrices.com and more than 250 similar websites that track gasoline prices at more than 140,000 gasoline stations in the United States and Canada.

Howard Pankratz: 303-954-1939, hpankratz@denverpost.com or twitter.com/howardpankratz