Ottawa motorists will want to wait until Friday to fill up the gas tank. Canadians for Affordable Energy president Dan McTeague says gas prices will drop 7 cents a litre at stations in Ottawa and across Ontario on Friday. The average price of gas will be 181.9 cents a litre, according to McTeague. McTeague tells CP24 that gas prices will drop again next week as refineries switch from summer blend to winter blend gasoline. “This sets the stage for next week’s seven-cent drop around Sept. 17, when refiners switch to cheaper blend winter gasoline,” McTeague said in an email to CP24. Gas was selling for 143.9 cents a litre this time last year. Meantime, the cost of diesel is set to hit an all-time high on Friday, according to McTeague. He says diesel prices will increase nine cents a litre to 245.9 cents a litre. With files from CP24