Charles River Marathon Invitational
Race Day Weather
Warm afternoon, adjust pace early
Runners will face a temperature increase from 62°F at the start to 75°F by the end, with humidity averaging 76%. Wind will be light, peaking at 9 mph from the WSW, making it a minor factor. As conditions warm, participants should start conservatively and adjust their pace in the later laps to manage heat effectively.
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Race Info
The Charles River Marathon Invitational is an invitation-only marathon in Boston, run on the same USATF-certified, ten-lap Charles River loop as the Charles River Marathon. Entry requires having finished a certified marathon since January 2024 within 20 minutes of a Boston qualifying time, with a limited number of fundraiser entries available. First run in September 2025, it drew a 73% Boston-qualifying rate among finishers. The race benefits the RACE Cancer Foundation's cancer research fundraising.
