The 20-cent-a-gallon border

Everyone’s noticed the upward creep in gas prices.

After plummeting from record highs late last year, prices have inched upward ever since January. That’s true across the board, but of course it’s often the differences in prices among regions that attract our attention — the steady difference of 15 to 20 cents a gallon between Spokane and Coeur d’Alene is the one that most often catches our attention.

Spokane’s prices are averaging $2.29 a gallon for regular unleaded, according to AAA. That’s up 22 cents from a month ago, and it’s 20 cents higher than Coeur d’Alene’s average. That’s a pretty typical difference in recent years — a year ago, it was a 16-cent spread between the cities, and when gas prices reached record levels last July, the spread was 12 cents.

Experts have said the difference results from a combination of factors: lower gas taxes in Idaho, generally higher wholesale gas prices as it’s pumped west from refineries in Montana, and the possibility that Washington gas retailers may have to raise their prices a bit to make up for business lost of Idaho.

Here’s how Tim Hamilton, executive director of Automotive United Trades Association, an Olympia-based non-profit that represents independent gas retailers, explained that final point to the Spokesman-Review in 2007.

” Washington dealers are forced to increase their margins to cover the loss of business from the transfer of sales from one side of the state line to the other,” he said, noting that an increased retail margin can add from 1.5 cents to 5 cents to the cost per gallon. “We call that a ‘death spiral’ in the gasoline business,” Hamilton said.

Here’s a more detailed picture of gas prices, based on the AAA Fuel Guage Report.

— In Spokane, the average price is $2.29 . It was $2.08 a month ago, and $3.59 a year ago. The record high was $4.19 on July 16, 2008. Here’s a link to the report. The city’s average price bottomed out around Christmas just below $1.50 a gallon, and has climbed steadily since then. Here’s a link to spokanegasprices.com, where you can chart gas prices against national averages and other cities — though the site doesn’t do Coeur d’Alene prices.

— In Coeur d’Alene, the average price is $2.09 . That’s well below last summer’s record price of $4.07 — but 20 cents higher than it was a month ago. Link to full AAA report.

— Both cities are higher than the national average, which is $2.06 , according to AAA. That’s down from a record last summer of $4.11.

Experts say they foresee the return of higher gas prices once the recession eases. The good news, for now, is that forecasts call for prices to stabilize through the summer. The federal government’s Energy Information Administration’s short-term outlook calls for average prices of $2.23 through the summer.

The bad news? The estimate is quite uncertain, as this wonkish disclaimer from the report makes clear.

However, because short-term prices can be quite volatile, weekly prices will be higher (or lower) than the monthly average .  In addition, if consumption turns out to be greater than projected in this Outlook , there could be increases in the monthly price averages.

So there’s that.

How have the changes in gas prices in the past year affected your life? Did you scale back, drive less, buy a more efficient car or take other steps to offset the peak prices last year? And have you adjusted in any way to the either the steep decline that followed, or the gradual upward creep we’re seeing now?