Charles River Marathon

Boston, United States of America · Monday 3 May 2027

RoadFull Marathon

Held in Boston during May, the Charles River Marathon takes advantage of one of the region's most recognizable natural features. The course winds along the Charles River, giving runners a tour through Massachusetts' largest city and its surrounding areas. Spring weather in Boston can be unpredictable, so participants should prepare for anything from cool mornings to warm afternoons, and the river corridor offers some shade from trees lining the water, though sections will expose you to direct sun. The course itself is refreshingly straightforward, staying almost entirely flat with just gentle rolling sections that barely register as hills. With under 70 meters of elevation gain over the full distance, this is a route where pace and consistency matter far more than fitness for climbing. Runners should expect a steady rhythm along paved roads, the kind of terrain where you can settle into a comfortable groove early and maintain it. The low elevation profile makes this a good option for time-goal racers, though the real variable will be weather conditions and how the river-side exposure affects you as the day warms up.

Difficulty Calculator

Your Marathon Time

Adjusted Time

3:51:30

Easy

Time difference: -8.5 minutes compared to a flat, road, temperate course.

Course Details

Elevation Gain65m

Elevation High5m

Elevation Low1m

Weather Forecast

High12°C

Low6°C

Chance of Rain8%

How hard is Charles River Marathon?

Easyharder than 4% of marathons

Flattest / easiestHardest

On our difficulty model, Charles River Marathon plays about 3 minutes faster than an average road marathon for a 3:30 runner. It ranks #1109 hardest of 1150 marathons we analyse, and #549 of 575 in United States of America. Use the calculator above to see the exact adjusted time for your own goal pace.

What will you run at Charles River Marathon?

Estimated finish times on this course versus the same effort on an average road marathon, based on its elevation, surface, and expected race-day temperature.

Average-course time	On Charles River Marathon	Difference
3:00:00	2:53:05	−06:55
3:30:00	3:22:20	−07:40
4:00:00	3:51:30	−08:30
4:30:00	4:20:34	−09:26
5:00:00	4:49:35	−10:25
5:30:00	5:18:31	−11:29
6:00:00	5:47:24	−12:36

Use the calculator above for your exact goal time. Want a prediction from your own training? Try the marathon time predictor.

Charles River Marathon 2027 Course Analysis

Charles River Marathon is a full marathon held in Boston, United States of America. It is scheduled for Monday 3 May 2027. The course is run on road surface with 65m of total climbing, with its high point near 5m above sea level.

Elevation Profile

This is a very flat course, with only 65m of total climbing and little change in altitude throughout. Flat profiles let you hold an even pace from start to finish, which makes this a fast, PB-friendly race.

Expected Race Day Weather

Based on historical weather data for May, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from 6°C to 12°C. This temperature range is widely considered optimal for marathon performance, allowing efficient heat dissipation without cold-related issues. There is a low chance of rain (8%), so dry conditions are likely.

Surface Type: Road

Charles River Marathon is run on road surfaces, which provide the fastest and most predictable conditions for racing. Road courses allow for consistent pacing and are typically the best choice for a personal best.

Looking for an easier marathon or a tougher challenge? You can also compare Charles River Marathon against other marathons to find the right race for your goals.

Marathons of similar difficulty

If Charles River Marathon fits your goal, these courses play out about the same on our difficulty model.

Charles River Marathon

Difficulty Calculator

Course Details

Weather Forecast

How hard is Charles River Marathon?

What will you run at Charles River Marathon?

Charles River Marathon 2027 Course Analysis

Elevation Profile

Expected Race Day Weather

Surface Type: Road

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