The best time to go to Castleton, Ontario, is during the summer months, from June to August, or in the early autumn, specifically September.Summer in Castleton offers the warmest weather, with average temperatures around 25°C. This period is superb for enjoying outdoor activities like hiking along the Ganaraska Forest trails or exploring the local farms and orchards. The Trent-Severn Waterway is also a popular spot for boating and fishing during these months. Families often find summer ideal for a visit, as the pleasant weather allows for full enjoyment of the area's natural attractions and agricultural experiences.September provides a beautiful transition as the leaves begin to change colour, creating stunning scenery, particularly around the Northumberland Hills. The weather remains mild, generally around 18-20°C, and there are fewer crowds compared to the peak summer season. This time of year is excellent for couples looking for a picturesque escape, perhaps enjoying a scenic drive through the countryside or visiting a local winery.