The best time to go to Brockville is during the summer months, from June to August, when the weather is warm and ideal for outdoor activities.During this period, the average daily temperatures range from 20°C to 27°C, superb for enjoying the St. Lawrence River. You'll find that all the boat tours, including those exploring the famous 1000 Islands, are in full operation. The Brockville Railway Tunnel, Canada's first railway tunnel, is also open for exploration during these months, offering a unique historical experience.Shoulder seasons, specifically May and September, also offer a pleasant experience with fewer crowds and comfortable temperatures. May sees average temperatures between 10°C and 18°C, while September is slightly warmer, ranging from 12°C to 20°C. Many attractions are still open, and the autumn colours in September can be particularly picturesque along the river. This is an excellent time for couples looking for a quieter getaway without missing out on the main sights.Winter, from December to February, is considerably colder, with temperatures often dropping below freezing. While some indoor attractions remain open, many of the river-based activities are unavailable.