A sharp price increase is on the way at gas stations across Ontario, including those in Windsor-Essex.
Ontario and Quebec will see a 14 cent per litre increase overnight Thursday.
The price for a litre of regular will rise to $1.79, the highest level seen since Aug. 2, 2022.
In Quebec, the price per litre is expected to climb to $1.88.
The sudden spike is being blamed on the higher cost of summer blended gasoline.
The cheaper winter blend won't return until the fall.
Patrick De Haan, analyst with Gas Buddy.com, told AM800's The Dan MacDonald Show this is the final step toward summer gasoline, the specifications changed yesterday, and that's why there's a big price difference.
"Now we've rolled to the summer specifications, which are required to ease air pollution through the summer months," he says. "Unfortunately, inventory is not quite as lavish as it is, so inventory is rather tight for summer gasoline because refineries just started producing here in the last few weeks. That's why the jolt is here - a change in the specifications."
De Haan says we do see a spike every year around this time, but it can be different in terms of how much of an increase it is.
"This year's supplies of winter gasoline were relatively plentiful, and so there were discounts on that winter gasoline to purge it from the system," he says. "Essentially, when you go from discounting the old merchandise to bringing in the new merchandise, there's generally a cost difference. This year, it's because supplies have not built up to adequate levels that there's a bit more pinch at the pump."
De Haan says he sees some light at the end of the tunnel and thinks the increases will slow down after the next few days.
"The price of oil is taming, typically, gas prices do not peak in the summer but in April or May," he says. "I think we're getting, to throw out a baseball analogy, we're probably in the 8th inning of the seasonal rise. We should be starting to see seasonal increases taper off."
De Haan adds another issue impacting prices: higher oil prices along with the federal government's carbon tax.
The carbon tax now stands at 3 cents per litre, which he says will always be a factor in making year-over-year comparisons.
De Haan says the current provincial average for a litre of regular is $162.9, compared to an average of $153.1 at the same time a year ago.
With files from CTV News