For a pleasant visit to Arlington, the best times to go are during the late spring (May to early June) and early autumn (September to early October).These periods offer comfortable temperatures, typically ranging from 15°C to 25°C, making outdoor activities enjoyable without the intense heat of summer. You'll find the weather ideal for exploring the area's natural beauty, such as hikes along the Columbia River or visits to nearby state parks.Summer (July and August) can be very warm, with temperatures often exceeding 30°C, which might be less comfortable for some travellers.