The figures include those who watched the coverage after it was broadcast, within a week of its original showing.
1.2 million is a new low for the Canadian Grand Prix, and is down by more than a quarter since 2016, when 1.77 million watched the highlights of the Montreal race.
Since 2016, the figure has fallen each year, with 1.39 million tuning in for the 2017 highlights, and 1.26 million a year later.
This shows a worrying trend for F1, and the sport's owners, Liberty Media, are trying to improve this downward spiral with the new rules for 2021, set to be released in October.
In comparison, the last 90 minutes of Jenson Button's incredible win in 2011 averaged 6.04 million viewers, and on Sky Sports F1, viewing figures only reached a meagre 423,000.