When Do The Clocks Change In Ontario 2025. 3, the first sunday of the month. Millions of ontarians will be losing an hour of sleep this weekend, after setting their clocks ahead for daylight time.

Sunday will mark the first day of daylight saving time with clocks “springing forward” one hour at 2 a.m. When you go to bed this saturday night, be sure to set your clock one hour ahead, because as of 3 a.m.