André Cantin, a meteorologist with Environment Canada, said the storm was the result of an "unstable air mass" during that period.
Cantin said it wasn't necessarily an "unusual storm," but the fact that it occurred in the early evening hours directly over the city made it more noteworthy.
A 32-year-old cyclist was critically injured by a lightning strike.
He was riding his bicycle near the intersection of Jeanne-D'Arc Avenue and St-Joseph Boulevard East — across from the Montreal Botanical Garden — when he was hit just before 6 p.m.
Bob Lamle, an Urgences-Santé spokesman, told CBC Montreal's Daybreak the man got hit by the lightning bolt on the side of his head.
"He had a burn hole at the base of his head," Lamle said.
He said the man was "unconscious and in a full cardiac arrest," but paramedics were able to revive him.
Lamle said he didn't have an update on the man's condition.