Preparing for the Half Distance Triathlon Boise means understanding the course and training with intention. This 70.3-mile event begins with a 1.2-mile swim in the clear, calm waters of Lucky Peak Reservoir, where temperatures average 72°F (22°C)—ideal for wetsuit-legal conditions. Athletes then take on a scenic 56-mile bike course featuring rolling terrain through the rural outskirts of Boise, transitioning downtown for a fast, flat 13.1-mile run along the Boise River Greenbelt. With summer ...