The Ironman Boise 70.3 begins in the pristine setting of Lucky Peak Reservoir, where athletes complete a single-loop 1.2-mile swim in Barclay Bay. The bay’s accessible location provides convenient entry and exit points for swimmers, creating an athlete-friendly start to the race.
Following the swim, participants embark on a picturesque bike course that showcases both rural and urban aspects of the Boise area. The rolling terrain takes cyclists through peaceful countryside roads and residential neighbourhoods.
The half-marathon portion features a flat, two-loop course that follows the Boise River. Runners benefit from abundant shade along the route, making the 13.1-mile run more comfortable even during warm race days.
Late June in Boise, Idaho typically presents warm to hot conditions for Ironman Boise 70.3 participants. Daytime temperatures commonly range from 27°C to 33°C (80°F to 92°F), with the potential to reach higher temperatures during heat waves. Early morning temperatures at race start can be generally more moderate, typically between 15°C to 20°C (59°F to 68°F).
The region experiences low humidity levels, usually between 20-40%, which can help athletes feel more comfortable despite the warm temperatures. However, the dry conditions and altitude (approximately 2,700 feet above sea level) make proper hydration crucial. Wind conditions are typically light to moderate in the morning, with speeds of 5-15 kilometres per hour (3-9 mph), though afternoon winds can become stronger.
Lucky Peak Reservoir’s water temperature in late June typically ranges from 18°C to 21°C (64°F to 70°F), making it wetsuit legal for most Ironman events. The reservoir’s temperature can vary based on recent weather patterns, snowmelt, and dam operations. The water conditions are usually calm in the early morning hours when the swim takes place, though wind-driven chop can develop later in the day.
The high desert climate of Boise means rainfall is relatively rare in June, with the month averaging only 2-3 days of precipitation. The area experiences abundant sunshine, with very clear skies being the norm. Athletes should be prepared for significant temperature increases throughout the race day and pack appropriate sun protection. The combination of altitude, dry air, and strong sun exposure makes heat management and hydration particularly important considerations for this event.
