Fuel prices appeared to cool like the coming of autumn after weeks of increases, with the average cost of gasoline falling to about $3.84 at the pump, while diesel fell almost a nickel to $4.59, according to the U.S. Energy Information Administration.

Here are the latest diesel fuel and gasoline statistics:

U.S. Regional Diesel Fuel Prices as of Sept. 18, 2023

• East Coast: $4.52

• Midwest: $4.44

• Gulf Coast: $4.28

• Rocky Mountain: $4.80

• West Coast: $5.69

U.S. Regional Gasoline Prices as of Sept. 25, 2023

• East Coast: $3.60

• Midwest: $3.64

• Gulf Coast: $3.35

• Rocky Mountain: $4.00

• West Coast: $5.26

“It’s been a mostly quiet week for the national average price of gasoline, with most states seeing gas prices cool off. But new and continued refinery issues in some regions have had an oversized effect on gas prices in some states, especially in Southern California, Arizona, and Nevada,” said Patrick De Haan, head of petroleum analysis at GasBuddy. “While most states are likely to continue seeing gasoline prices fall in the week ahead, any new refinery issues as others begin maintenance could be problematic. For diesel prices, however, the opposite is playing out, with prices that continue to rise as demand for diesel strengthens. Overall, the largest issues impacting gas prices remain refinery disruptions, but also the price of oil, which has held around $90 per barrel as Saudi Arabia and Russia maintain significant production cuts.”

Gasoline is now 22 cents more expensive than it was this time last year on average, according to the U.S. Energy Information Administration. Diesel climbed more than 9 cents per gallon during the past week, but remains 33 cents lower than it was in 2022.

Here are the latest diesel fuel and gasoline statistics:

U.S. Regional Diesel Fuel Prices as of Sept. 18, 2023

• East Coast: $4.54

• Midwest: $4.49

• Gulf Coast: $4.35

• Rocky Mountain: $4.86

• West Coast: $5.69

U.S. Regional Gasoline Prices as of Sept. 18, 2023

• East Coast: $3.65

• Midwest: $3.71

• Gulf Coast: $3.43

• Rocky Mountain: $4.07

• West Coast: $5.16

Gas price increases during the past week are attributable to ongoing refinery challenges in the western United States, according to Patrick De Haan, head of petroleum analysis at GasBuddy:

“With the transition back to cheaper winter gasoline now upon us in nearly every state, we should see prices eventually cooling back off. But if refinery issues continue to develop or linger, especially now that we’re entering maintenance season with less available capacity online, the expected decline could certainly be offset. In addition, with oil prices now above $91 for the first time in nearly a year, there remains some offset from the rising price of oil thanks to Saudi Arabia and Russia’s war on low oil prices, now in its third month.”

On average, gasoline and diesel prices continued to climb across the United States, according to the U.S. Energy Information Administration.

Here are the latest diesel fuel and gasoline statistics:

U.S. Regional Diesel Fuel Prices as of Sept. 11, 2023

• East Coast: $4.48

• Midwest: $4.43

• Gulf Coast: $4.21

• Rocky Mountain: $4.81

• West Coast: $5.53

U.S. Regional Gasoline Prices as of Sept. 11, 2023

• East Coast: $3.63

• Midwest: $3.68

• Gulf Coast: $3.37

• Rocky Mountain: $4.01

• West Coast: $4.97

“The national average hit some road bumps over the last week after starting to decline early in the week. The second half saw the national average rise as gas prices in the Corn Belt started spiking, pulling the average price in the US along with it,” said Patrick De Haan, head of petroleum analysis at GasBuddy. “In addition, the West Coast saw more refinery snags, pushing gas prices higher, and so areas of the West Coast got punched along with the Corn Belt states. Over 10 states saw prices rise by over 10 cents per gallon compared to last week, while some like Iowa and Minnesota have seen average prices spike by over 30 cents per gallon. There is some good news for those in the hardest hit states in the Midwest, however, as gasoline prices should start to level off and even decline by mid-week."

The month of September started mixed for school bus fleet fuel prices across the United States, with gasoline down slightly and diesel creeping upward just a bit on average, according to the U.S. Energy Information Administration. Gasoline prices increased in the Rocky Mountain and West Coast regions, while diesel saw mild decreases along the East Coast and in the Midwest.

Here are the latest gasoline and diesel fuel statistics:

U.S. Regional Diesel Fuel Prices as of Sept. 4, 2023

• East Coast: $4.47

• Midwest: $4.38

• Gulf Coast: $4.17

• Rocky Mountain: $4.73

• West Coast: $5.39

U.S. Regional Gasoline Prices as of Sept. 4, 2023

• East Coast: $3.65

• Midwest: $3.63

• Gulf Coast: $3.36

• Rocky Mountain: $4.00

• West Coast: $4.91

The slight relief may be due to the fact Hurricane Idalia didn't inflict any damage on vital energy infrastructure. Wrote Patrick De Haan, head of petroleum analysis at GasBuddy:

"Hurricane Idalia steered well clear of significant energy infrastructure, leading to zero impact on gas prices. With the switch back to winter gasoline less than two weeks away, we could eventually see more downward pressure on gas prices. However, any disturbances that threaten the Gulf could delay any decline between now and then, creating a bit of a bumpy ride for the next week or two before more relief arrives toward late September.”