The 1927 Nova Scotia hurricane was the deadliest tropical cyclone striking Canada in the 20th century. The first observed storm of the season, this cyclone developed from a tropical wave over the deep tropics of the Atlantic Ocean on August 18. Initially a tropical storm, it moved west-northwestward and intensified into a Category 1 hurricane on the modern day Saffir–Simpson hurricane wind scale by August 19. The storm intensified significantly over the next few days, and by August 22, it peaked as a Category 3 hurricane with maximum sustained winds of 125 mph (205 km/h). Around that time, the system began curving northwestward and later northward. By August 23, it turned to the north-northeast and then began weakening on August 24. Thereafter, the storm accelerated toward Atlantic Canada. Late on August 24, the hurricane struck near Yarmouth, Nova Scotia, as a Category 2 hurricane, just before becoming extratropical.

The 1927 Atlantic hurricane season was a relatively inactive season, with eight tropical storms, four of which became hurricanes. One of these became a major hurricane – Category 3 or higher on the modern day Saffir–Simpson scale. The first system, a tropical depression, developed on August 13, while the final cyclone, a tropical storm, merged with a cold front on November 21. No hurricane made landfall in the United States, in contrast to the four that struck the U.S. in the previous season.