The best time to visit Waltham is during the summer months, from June to August, when the weather is warm and conducive to outdoor activities, or in the fall, from September to October, for stunning foliage.Summer offers the warmest temperatures, with average highs around 25°C (77°F). This period is ideal for enjoying the Ottawa River activities, such as kayaking, fishing, or simply relaxing by the water. Many local events and markets are also in full swing during these months, providing opportunities to experience the local culture. Families often find summer to be the most convenient time for a visit due to school holidays and the wide range of outdoor options.For couples or travelers who appreciate natural beauty, the fall season presents a picturesque landscape as the leaves change color. The cooler, crisp air, with average highs around 15°C (59°F), is superb for hiking or scenic drives through the surrounding forests.