Oil market volatility continues to play havoc at the pumps, with gas prices set to jump by eight cents on Saturday.En-Pro’s Chief Petroleum Analyst, Roger McKnight, tells CityNews that the change over to summer gas from the winter blend is responsible for most of the price increase, with changes in the posted futures markets accounting for the rest.“The 8-cent increase in eastern Canada effective [Saturday] is made up of three cents due to the futures price change and five cents for the switch from winter to summer formulation gasoline,” he said. “The formulation switch is mandated by the US EPA, which Canada dutifully follows. This is not an oil industry decision.”The price jump is expected to reverse once the Government of Canada’s temporary suspension of the federal Fuel Excise Tax on gasoline, diesel and aviation fuels comes into effect across Canada on April 20.Related:Liberals suspend federal fuel excise taxes until Labour DayThe suspension is in response to the soaring price of oil due to the ongoing U.S.-Israel-led war on Iran and will remain in place until Labour Day. It’s expected to lower the price of regular gas by 10 cents/litre and diesel by 4 cents/litre.However, McKnight says this will not be reflected at the pumps until Wednesday.“Normally, daily price movements follow changes in the posted futures markets that are then reflected in the changes at the wholesale level 24 hours later. Thereafter, there is a one-day delay before the original change hits the pump price,” he explains.McKnight adds that prices are currently being “dramatically affected” by the war and the headlines that drive speculation and push prices up or down, “depending on the rumour flavour of the day.”“Currently, the headline being read is that the Strait of Hormuz is open. This will be interpreted by the traders that oil will flow once again and drive down the price of crude and gasoline,” he said.