The audience numbers for the film, which went out last Friday, made it the top entertainment show on cable for the day overall and in the key 18-to-49 demo.
Space will repeat the film today in a 9pm E.T. slot.
The ratings winning performance in Canada follows the show generating an enormous amount of social media buzz after its debut on Syfy in the US. At its peak it was getting 5,000 tweets per minute and generated almost 400,000 in all.
The TV ratings were solid although did not match the spectacular social media numbers with the show attracting 1.4 million viewers, about the average for a Syfy TV movie.
Sharknado is produced by The Asylum whose other titles include Mega Shark Versus Giant Octopus and Snakes on a Train. It tells the story of a group of people investigating why sharks are falling from the sky.