Summer gas is here. What does that mean for sky-high prices?

Since betimes process, fill your tankful has meant voidance your wallet.

Earlier this week, the national average for a litre of gas was just over $1.77, up from $1.26 before the United States and Israel launched their attacks on Iran, halting movement through the Strait of Hormuz.

To ease some of that pain, Prime Minister Mark Carney announced he is temporarily removing the federal excise tax on gas and diesel — a move that will cut the cost of gasoline by 10 cents per litre and four cents per litre of diesel starting on Monday.

But as motorists anticipate some relief, April is often when gas prices climb across the board — even when a sustained geopolitical conflict isn't disrupting the supply.

You might assume gas prices jump in the summer as more Canadians hit the road.

That spike in demand is a factor, but there's another reason the price of gas climbs in the warmer months — manufacturers switch from a winter blend of gasoline to a summer blend.

Carol Montreuil, vice-president of the Canadian Fuels Association, explains that changes in temperature and environmental concerns require the components of gas to be altered between seasons.

"Without vapour, the ignition of the car simply doesn't work. And to that effect, there are some components that are put in the gasoline in the winter to ensure that there's a certain level of vapour in the cylinders so that the car will ignite and start," he said.

"In the summer, it's the other way around. The weather gets really warm, and there's a real risk that there might be too much vapour. So, we have to adapt summer gasoline to remove these components that are responsible."

While a summer blend may sound like a refreshing drink to be sipped on a summer patio, it actually is a cleaner and more fuel-efficient product that also translates to higher prices at the pump.

Summer fuel blend standards are managed by the federal government and implemented on April 15.

It's possible — but it depends on what happens in the next few weeks.

Montreuil said the impact on prices will be better understood on Monday, when the tax vacation and summer gas prices are simultaneously in effect.

"The reduction of this excise tax on Monday is a sizable number, and we will be able to track it hoping that everything else stays the same and that there's no additional escalation in the Middle East," he said.

"So it's going to be very easy to verify that indeed this will benefit the consumers."

Werner Antweiler, a professor of economics at the University of British Columbia's Sauder School of Business, said prices in the diesel market are unlikely to come down.

"There is some pressure that is actually coming from the demand for refined diesel fuel in international markets. And there is a shortage around the world that's driving up prices," he said.

"That is something that a four cents a litre cut isn't going to really offset."

While gas prices are up across the country, some regions have seen higher prices than others.

Earlier this week, B.C. Experienced the highest prices with an average $1.99 per litre, while Alberta had the lowest prices, averaging $1.66.

Antweiler said transportation and taxation differ between provinces, translating to price differences.

"You always find the lowest prices in Alberta because it's right where the crude is being produced," he said.

"In the eastern part of the country, we are importing our crude oil from many places, including the United States. And in Western Canada, we rely on domestic production and that is shipped from Alberta."

Three municipalities in Canada —Vancouver, Victoria and Montreal — also charge municipal taxes on gasoline.

Regions like Newfoundland and Labrador face high prices because of unique logistical challenges of transporting gas.

On Friday, Iran's foreign minister announced that passage for all commercial ​vessels through the Strait ​of Hormuz would ​open following a ceasefire agreement reached in Lebanon.

President Donald Trump said the U.S. Naval blockade on Iran will remain in place until a deal with Tehran is struck — but the news quickly sent oil prices plunging.

Antweiler said even if there is a permanent end to the war, and tanker traffic is fully restored in the Strait of Hormuz, it could take months for prices to recover because of a massive backlog of demand.

"Many places around the world have been using their reserves and as they're getting depleted, they will also try to replenish them," he said.

"So no matter how soon this conflict ends, there will be significant long-term repercussions that will keep prices elevated for some time."

So far, Alberta has announced it is sticking to its gas tax formula.

B.C. Has formed a task force to help the province through economic uncertainty, but said "our focus is broader than fuel prices alone and includes protecting supply chains for essential goods."

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