Gas prices often move higher in late summer as refinery maintenance, hurricane risk, and regional fuel rules tighten supply across the US. For August, the biggest likely increases are concentrated in states that already run above the national average or depend on limited supply lines, based on recent AAA data, Energy Information Administration market reports, and seasonal price patterns. This list looks at 10 states where drivers may see the sharpest month-ahead pressure at the pump.
California
California regularly posts the highest average gas prices in the country, and AAA data in recent summers has shown the state running more than $1 above the US average. The Energy Information Administration has also noted that California’s cleaner fuel blend and limited in-state refining options can push prices up quickly when supply tightens.
In August, that matters more because West Coast refinery maintenance and wildfire disruptions can reduce deliveries within days. State figures from the California Energy Commission have shown that even a single refinery outage can affect millions of gallons of supply, and California drivers typically feel that first.
For residents in Los Angeles, San Diego, and Sacramento, the practical effect is simple: pump prices can rise faster here than in most states, even when crude oil moves only modestly. Officials have not identified a single August event statewide, but California’s structure keeps it near the top of risk lists.
Nevada
Nevada is closely tied to California’s fuel system, which means price spikes there often move east into Las Vegas and Reno. AAA averages in prior August periods have shown Nevada ranking near the top five states for gasoline prices, largely because much of its supply comes through the same regional network.
The Energy Information Administration has said Nevada is vulnerable to pipeline and refinery constraints outside its borders. That leaves fewer backup options than states with Gulf Coast access or more local refining capacity.
For drivers in Clark County and Washoe County, that can translate into quick week-to-week changes. A jump of 10 to 20 cents in a short stretch is not unusual during supply squeezes, according to historical AAA tracking, and August often brings exactly that kind of pressure.
Arizona
Arizona often lands high on late-summer gas price lists because Phoenix relies heavily on fuel shipped from California and Texas. EIA regional supply data has shown that when either route gets tighter, Arizona prices tend to respond quickly, especially during high-demand travel periods.
AAA price reports during several recent Augusts showed Arizona climbing above the national average by a noticeable margin. Maricopa County usually sees the biggest effect because of its large population and heavy driving demand.
That means residents in Phoenix, Mesa, and Scottsdale may see some of the sharper August increases in the Southwest. The state has not announced a new fuel tax change for August, so the main issue remains supply cost and regional distribution limits already documented by federal energy data.
Oregon
Oregon does not refine much of its own gasoline, which leaves it more exposed to West Coast supply shifts. The Energy Information Administration has repeatedly identified Pacific Northwest markets as sensitive to refinery issues in California and Washington, especially when inventories are already below typical seasonal levels.
Portland prices can move quickly in August because the state also sees heavy tourism traffic during the summer. AAA tracking has shown Oregon frequently sitting well above the national average during peak travel weeks.
For residents, the biggest takeaway is that Oregon’s price path often follows broader West Coast stress rather than local events alone. State officials have not flagged a single August trigger, but the underlying supply setup has been documented for years.
Washington
Washington drivers are starting from a relatively high baseline, and the state has remained among the most expensive gas markets in the country in recent AAA reports. Fuel analysts have pointed to refinery maintenance, carbon-related policy costs, and regional supply balance as key reasons prices can climb faster here.
The state also depends heavily on a handful of large refineries in the Pacific Northwest. When output drops, the effect can be felt from Seattle to Spokane within the same pricing cycle.
For August, that means Washington remains one of the most exposed states for noticeable increases. Officials have not released any statewide estimate for an August jump, but past summer data shows the state often absorbs increases faster than much of the country.
Hawaii
Hawaii is almost always near the top of state gas price rankings because it depends on fuel shipped over long distances. The EIA has said transportation costs and isolated island markets make Hawaii more vulnerable to global supply and freight shifts than most mainland states.
Honolulu drivers already pay a premium compared with the US average, and that can widen during heavy travel months like August. Limited local competition in some areas can also keep declines from reaching consumers as fast as mainland states.
The practical impact is straightforward: even small increases in wholesale or shipping costs can show up quickly at retail stations. State-specific August pricing has not been formally projected, but Hawaii’s market structure consistently supports above-average summer pressure.
Alaska
Alaska’s gas prices are shaped less by interstate competition and more by transport, geography, and storage costs. AAA has often placed Alaska among the higher-priced states, even when crude production news from the state itself suggests lower input costs.
That is because retail gasoline in Alaska still has to move through a challenging distribution network that serves widely separated communities. In places outside Anchorage and Fairbanks, local price swings can be especially sharp.
For August, residents should expect the same pattern: higher costs can arrive even without a single headline disruption. Federal energy data has long shown that remote logistics can push Alaska prices up faster than the national trend during busy travel periods.
Illinois
Illinois stands out in the Midwest because taxes and fees add more to the pump price than in many neighboring states. The Illinois Department of Revenue and tax policy trackers have shown the state’s total gasoline tax burden ranking among the nation’s highest in recent years.
Chicago-area prices also react quickly to shifts in Great Lakes refining and summer-grade fuel costs. AAA state averages have often put Illinois near the top of Midwest price charts during August.
That does not mean Illinois will match California, but it can still post one of the steeper month-to-month increases in its region. For drivers in Cook County and nearby suburbs, tax structure and refining costs remain the most documented pressure points.
Pennsylvania
Pennsylvania has long been known for carrying one of the highest state gas taxes in the US. Data from state revenue agencies and transportation funding reports has repeatedly placed the commonwealth near the top on per-gallon tax burden, which keeps retail prices elevated even before supply changes hit.
That creates less room for relief during late summer. When wholesale costs rise in the Northeast, Pennsylvania drivers often see the effect clearly at the pump in Philadelphia, Pittsburgh, and Harrisburg.
For August, that makes the state a strong candidate for one of the bigger increases east of the Mississippi. No statewide August spike has been officially forecast, but tax-heavy pricing gives Pennsylvania less cushion than lower-cost neighbors.
Indiana
Indiana is one of the more volatile gas price states in the Midwest because of its pricing formula and close connection to Chicago-area fuel markets. Market tracking from GasBuddy and AAA has shown Indiana posting sharp weekly swings, including double-digit cent changes over short periods.
That volatility tends to show up in summer, when demand remains high and regional refinery issues can ripple across northern Indiana. Indianapolis, Gary, and South Bend often move on different timelines, but the statewide average can still jump quickly.
For August, Indiana rounds out this list because it does not need a major disruption to see a notable increase. Historical pricing data shows the state can climb faster than nearby Ohio or Kentucky when regional costs start moving.
