Charles River Marathon
Race Day Weather
Cool conditions, adjust for wind
Runners will face a temperature starting at 45°F and peaking at 52°F, with an average humidity of 64% and a dew point of 35°F. Wind from the NW at 18 mph, gusting to 30 mph, will create a steady headwind throughout. Competitors should consider pacing adjustments to account for wind resistance and stay hydrated as they navigate these conditions.
Pace Calculator
Enter a finish time to see what race day does to it.
Get forecast alerts for Charles River Marathon
We'll text or email you when the forecast shifts — so you can adjust gear, pacing, and strategy. Max one per day.
Get your personalized Charles River Marathon race plan
A mile-by-mile breakdown of where your time goes, weather-adjusted splits, fueling timeline with aid stations, packing checklist, carb tracker, spectator guide, all built around your goal and race-day conditions.
Race Info
The Charles River Marathon offers a flat, fast, and USATF-certified 42.2-kilometer course along Boston's scenic Charles River, starting and finishing at Herter Park. Runners complete ten laps on a 2.6-mile loop, with over 49% of finishers qualifying for the Boston Marathon in recent years. This event combines competitive racing with a supportive atmosphere, featuring live DJ music and a focus on fundraising for cancer research.
