Why it's hard to predict if gas prices will go up or down

(GasBuddy) The nation’s average price of gasoline has fallen for the second straight week, declining 3.8 cents compared to a week ago and stands at $3.04 per gallon, according to GasBuddy® data compiled from more than 12 million individual price reports covering over 150,000 gas stations across the country. The national average is down 4.7 cents from a month and is 29.9 cents per gallon lower than a year ago. The national average price of diesel has decreased 1.9 cents in the last week