It's time for a mid-summer update on gasoline prices, and its not necessarily what everyone is or was hoping for. Some of you likely already realize that gasoline prices this year have been mesmerizing. Up, down, up, some regions saw spikes, others did not- but the bottom line I'll look at is the national average.

For the comparison, I'm using May 15 through today, and for 2012, I'll use data from May 15 through September 15.

So far for the summer of 2013 (using the start date of May 15), the national average has peaked at $3.69/gallon, on May 21, and bottomed out at $3.49/gallon on July 4. The average so far this summer comes in at $3.61/gallon.

In 2012, using the start date of May 15 through July 25, the national average had peaked at $3.74/gallon and bottomed out at $3.38/gallon on July 4. (Are you noticing that prices tend to bottom out around July 4 before they start to rise again?). In 2012, the average price between May 15 and July 25 was $3.53/gallon.

So far through today, that leaves the national average about 8-cents per gallon higher than what it was in 2012. With demand running slightly higher this year (cumulative average 361.7 million gallons per day for the year- a low average given that summer driving season sees higher consumption), U.S. motorists so far this summer have spent $2.08 billion more on gasoline than they had last year through July 25. (72 days times 8c/gallon, times 361.7 million gallons/day- this is a rough estimate)

2012 saw summer time (May 15-Sept 15) gasoline prices average $3.61 per gallon as prices rose in the second half of the summer, and there's a possibility that 2013 prices will rise in a similar way should there be a flurry of activity in the tropics that makes an impact on refining and oil production.