Gas prices are stabilizing in the Mother Lode and throughout Northern California after skyrocketing this summer.
Although all but two metro areas in Northern California saw at least a 4-cent rise per gallon of gas over the last month, the prices have been increasing at a slower rate than previous months.
Northern California's average for unleaded gas was $4.18 per gallon on Tuesday, which is 8 cents higher than last month's average, according to AAA Northern California. However, the $4.10 average reported on Aug. 14 was up 39 cents from the July 10 average.
The rates are consistent with the statewide averages.
California motorists saw an average of $4.17 on Tuesday, which is 10 cents higher than last month. However, the state saw a much greater increase from July to August, when the average escalated by 40 cents.
AAA attributed the spike across the Pacific Northwest and Nevada largely to the August fire at the Chevron refinery in Richmond. The facility produces at least 15 percent of the state's fuel, according to the Associated Press.
Although AAA does not provide specific numbers for Tuolumne and Calaveras counties, prices at Sonora gas stations ranged from $4.03 to $4.19 on Tuesday, according to Californiagasprices.com.
Trailing Hawaii, California has the second highest average for unleaded gas prices in the United States. The state average is 33 cents higher than the national average of $3.84. The national average is up 14 cents from last month.
Overall, the U.S. saw a spike similar to that of California from July to August, with a 32-cent increase in the average gas price.
AAA Northern California spokesperson Cynthia Harris said several factors may have contributed to the nationwide upsurge such as instability in the Middle East, higher fuel demand due to summer road trips and the halting of production during Hurricane Isaac as a precaution.
"Any time there is a hint that there may be a disruption … prices shoot up," she said.
Harris added that demand for gas has been slightly up over the past week across the U.S., but AAA expects demand to drop off as the busy summer driving period comes to an end.
Refineries have already started to switch from the summer blend of gas to the less-expensive winter blend, she said.