Half Distance Triathlon Maine: Terrain-Specific, Structured Preparation The Half Distance Triathlon Maine features a fast, current-assisted 1.2-mile river swim, a hilly 56-mile bike through the Kennebec River Valley, and a mostly flat 13.1-mile run through shaded towns along the river. With water temperatures averaging 69°F (21°C) and race-day air temps around 75°F (24°C), this course presents specific physical demands—strong early pacing, sustained climbing on the bike, and controlled effort ...