The best time to visit Niagara Falls, Ontario, is typically from late spring to early autumn, specifically May through October, to fully enjoy the outdoor attractions and pleasant weather.
During these months, the weather is generally warm and comfortable, with average temperatures ranging from 15°C to 25°C. This period allows for the full operation of popular boat tours that get you close to the falls, as well as the Whirlpool Aero Car and other outdoor activities. The Queen Victoria Park, which runs alongside the Niagara Parkway, is in full bloom, offering lovely scenic walks and photo opportunities.
Couples looking for a romantic getaway will find May, June, September, and October particularly appealing. The crowds are generally smaller than in the peak summer months, allowing for a more relaxed experience. You can enjoy strolls along the Niagara River, explore the vineyards in the nearby Niagara-on-the-Lake region, and dine at restaurants with fewer reservations needed. The evenings can be quite pleasant for enjoying the falls illuminations.
For families, July and August are ideal. All attractions are open, and there are often additional family-friendly events and entertainment. While it's the busiest time, the longer daylight hours mean more time for sightseeing, and the warmer weather is great for enjoying water-based activities and the various theme parks and entertainment venues along Clifton Hill.