If you need to fill up your car with gasoline, Tuesday might be the day to do so.

According to our partners at Tomorrowsgaspricetoday.com, gas prices will increase 3.4 cents at midnight to 136.8 cents a litre at most stations in the Greater Toronto Area.

Gas watcher Dan McTeague says there's no absolutely reason for the huge increase.

"This was not driven by market fundamentals or anything that bears any resemblance to market reality. This is simply pure monopoly pricing and they decided to flex their muscles in advance of any type of news that would justify those kinds of increase."

McTeague says the Canadian oil refineries maybe making assumptions on what Thursday's announcement from the U.S. Federal Reserve will be and whether they plan to stimulate the economy.

"It's a little bit of jumping the gun and unfortunately we're paying a very heavy and steep price for a complete and utter lack of competition at the refinery level in Toronto and across most of Canada," says McTeague.

McTeague also add that refineries can't use the excuse that supplies have been affected by Hurricane Isaac because things have been are back to normal in the U.S.

Gas prices at this time last year was just over $1.27 a litre.