A week ago, a federal agency announced its latest forecast for gas prices, which are expected to remain stable through the summer, averaging under $3.80 nationwide. While the overall average may indeed stay fairly flat, prices in individual states could fluctuate dramatically. That’s just what’s happened in the past week, with prices in one state dropping 14¢ per gallon—and rising over 14¢ in others.
For the country as a whole, gas prices have kept up a slow, steady decline over roughly a month’s time. According to AAA’s Fuel Gauge Report, the current national average as of Tuesday was $3.727, which is about 4¢ less than the week before, and 17¢ cheaper than a month prior. By late April, gas prices had decreased to the point that they were cheaper than the year before, and at this point last year, the average gallon cost nearly 25¢ more than it does right now.
This isn’t to say that gas prices are dropping everywhere. Not at all. Consumer Reports’ weekly gas price roundup notes that gas prices have declined in every region of the country with one notable exception: the West Coast. For the whole coast, gas prices have increased 12¢ per gallon over the past week.
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A GasBuddy post reports that the average per-gallon increase in California registered at 14¢ during the last week, and that prices rose as much as 17¢ in spots such as Santa Barbara and Orange County. Gas prices in Washington also increased 14¢ in a single week’s time, and Oregon drivers have gotten hit the hardest, with prices that are 17¢ per gallon more expensive than one week ago.
The post explains that while prices at the pump are tied to the price of crude oil—which has been decreasing—there are still explanations for why the West Coast drivers have been paying more:
If refineries aren’t processing enough oil, there won’t be enough gasoline. That’s the case here- supply has tumbled as refineries suffer various small blips, reducing the amount of gasoline available, thus causing some panic amongst traders, boosting the value of the gasoline that is available.
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Analysts cited in the Los Angeles Times, which lists the one-week rise in gas prices at 15.4¢ and the latest statewide average at $4.367 per gallon, also place the blame on refinery problems.
The story is quite different in much the country, especially in the Midwest and states such as Michigan. The Detroit Free Press reports that prices in Michigan have fallen 14¢ per gallon over the past week, bringing the statewide average to $3.69—or 45¢ cheaper than prices were a year ago at this time.
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Gas price hikes related to refinery issues are expected to be temporary, so, in theory, relief at the pump will come to West Coast drivers sometime in the near future. Based on how screwy gas prices have been this year, though, by the time prices should be decreasing in California and Oregon, it wouldn’t be surprising if some other issue(s) arose causing prices to rise for some reason or another, to the dismay and confusion of drivers everywhere.
Brad Tuttle is a reporter at TIME. Find him on Twitter at @bradrtuttle. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.