The national average price of gas held steady at about $4.50 per gallon, but one analyst predicts drivers could be in for another price jump as many Americans prepare to hit the road for Memorial Day weekend.

“The national average price of gasoline spent much of last week drifting lower after jumping early in the week as oil prices softened on hopes that diplomatic progress between the U.S. and Iran could help ease supply concerns,” Patrick De Haan, head of petroleum analysis at GasBuddy, said in a blog post. “However, that optimism faded after President Trump’s meeting with China’s Xi Jinping failed to produce a breakthrough on Iran, while renewed warnings toward Tehran have helped push oil prices higher again.”

De Haan added: “With global oil inventories continuing to trend toward historically tight levels, markets remain extremely sensitive to geopolitical developments and potential supply disruptions. As a result, gasoline and diesel prices are likely to remain volatile, and with Memorial Day approaching, any sustained increase in oil prices could begin pushing retail fuel prices higher again in the weeks ahead.”

The predictions come as gas prices have jumped from a national average of $2.98 on Feb. 28, the day the United States and Israel launched military strikes against Iran, to the present average of $4.51, according to the AAA Auto Club.

What Causes Variance in State Gas Prices?

Regional differences in gas prices can be explained by several factors, according to the U.S. Energy Information Administration.

The agency listed the following reasons for regional gas price differences:

• Differences in state and local gas taxes.
• Distance from supply.
• Supply disruptions.
• Retail competition and operating costs.
• Environmental programs.

“Retail gasoline prices tend to be higher the further gasoline must be transported to the point of sale because transportation costs are higher,” the agency said. “Anything that slows or stops gasoline production can result in increased bidding for available gasoline supplies. Prices at gasoline stations are often highest in locations with fewer gasoline stations.”

Which States Have the Highest Gas Prices?

In addition to the 18-cent federal gas tax that every driver pays at the pump, each state adds its own local gas tax.

Here are the top 5 states with the highest gas prices, including the federal tax, along with their current gas price averages as of May 18 and one week ago on May 11, according to AAA:

1. California

• May 18 gas price average: $6.15
• May 11 gas price average: $6.15

2. Washington

• May 18 gas price average: $5.77
• May 11 gas price average: $5.76

3. Hawaii

• May 18 gas price average: $5.63
• May 11 gas price average: $5.65

4. Oregon

• May 18 gas price average: $5.33
• May 11 gas price average: $5.32

5. Alaska

• May 18 gas price average: $5.28
• May 11 gas price average: $5.26

How to Save on Gas This Weekend

Here are five tips on ways to save on gas before you hit the road for Memorial Day weekend:

1. Skip premium gas

PennyHoarder.com said that “higher-octane gas isn’t necessary or beneficial in most cars, so you’re just spending more money when you buy premium.”

2. Use gas price apps to find the cheapest gas near you

Drivers can use apps like GasBuddy, Waze, or AAA to compare prices at nearby stations. Mapping apps like Apple Maps and Google Maps also now show prices at many stations when drivers use their “gas near me” features.

3. Save with grocery store fuel rewards programs

Many grocery stores offer rewards programs that give shoppers points they can use for discounts at nearby gas stations. Sign up at your nearby grocery stores, and make sure you link your purchases to the same account each time.

4. Use credit card points for fuel discounts

Many credit cards offer points for purchases that can later be used for things like travel. Many of those rewards can also be used for gas discounts.

5. Pay cash for gas when stations offer lower prices

Some gas stations offer lower prices to customers who pay with cash instead of a credit card. In some cases, paying with cash can save you 10 cents or more per gallon.

“It’s their way of avoiding card processing fees,” PennyHoarder said about gas stations offering cash discounts.