The average U.S. retail price of regular gasoline rose from $3.25 per gallon on December 17, 2012, to $3.78 per gallon on February 25, 2013. The increase is not unusual, as gasoline prices typically rise for an extended period around the first half of every year, although in some years, including this year, the price increase actually started in December.
The 16% rise from December 17 through February 25 was smaller than price increases in 9 out of the previous 10 years (see chart above). In absolute terms, this year's rise was the fourth smallest increase since 2003. The price fell by 24 cents per gallon to $3.54 between February 25 and April 15. If the average price does not rise above $3.78 per gallon again this season, the 2013 seasonal price increase will have the earliest ending date since the U.S. Energy Information Administration (EIA) began reporting weekly retail gasoline prices in 1991.
Although gasoline prices routinely increase from their winter lows through much of the first half of the year, the timing and duration of the increase varies (as shown by the blue shaded areas in the graph below). Over the past 20 years, the average period of rising prices in the spring has been 16 weeks, with the increase typically beginning in early February and ending around Memorial Day. In the past 10 years, the average duration of the price increase grew to nearly 19 weeks, with the increase typically beginning in early January and ending in mid-May.
In most years, the extended period of increasing prices ends by the end of May even though peak gasoline demand tends to be in June, July, and August. Notable exceptions occurred in 2006, when MTBE (Methyl Tertiary Butyl Ether) was phased out in most of the United States and refinery disruptions following Hurricanes Katrina and Rita in the prior fall significantly delayed normal maintenance schedules; and in 1994, which had a late second-quarter spike in crude prices.
While periods of increasing prices always garner attention, especially when prices are at or near historic or seasonal highs (as they are this year, and were during 2011, and from 2003 to 2008), these data show the increase in early 2013 was somewhat predictable, with the prices over the past 10 years increasing by an average of 36% from their seasonal low to their seasonal high.
These seasonal increases are the result of several factors, including: