2027 RACE BRIEFING
Boston Marathon
−1:57 versus your goal from a single 09:00 five-year ERA5 calendar-window mean snapshot.
Prepare for Boston's April race with historical weather context, the reference route and an even-pace reference for your goal time.
Explore your pace planZoom to drag the route. Keyboard: + / −, arrows, Home to reset.
2026 course reference. Check the organiser’s current course.
Race-day weather
Good preparation starts before the forecast.
Race-day forecasts appear here within 15 days of the event, when data is available. Until then, explore the course and historical weather below.
Explore historical weatherWhat the weather may cost
RunWeather’s shared pace model estimates the effect of one weather hour at your goal effort. It is a planning preview, not a predicted finish time or a full course simulation.
Snapshot at 09:00 local using five-year ERA5 calendar-window mean. Route climbing, turns, shelter, fuelling, fitness, heat adaptation and wave timing are not modelled here. Rain is excluded because a probability is not a measured rain rate. Explore the pace model.
What the course asks of you
Boston runs from Hopkinton to Boylston Street, with the Newton Hills later in the course. The displayed reference route is from 2026; confirm the upcoming edition with the B.A.A.
- Elevation
- 138 m
Hover or drag to explore. Use ← → when focused.
Keep the opening effort controlled so the later Newton Hills fit your overall plan.
Check conditions near both Hopkinton and Boston; one city forecast cannot describe the whole course.
Allow for the pre-start wait when deciding which extra layers to bring.
What mornings like this have looked like
A useful range for planning Boston Marathon: hourly weather near Boston for the same calendar date ±5 days in 2021–2025. These are city-grid samples, not past race editions or a forecast.
The five-year picture
- Air temperature
- 10°C
- Humidity
- 60%
- Wind
- 12 km/h
- Hours with rain
- 5%
Hover or drag to explore. Use ← → when focused. Shading: middle 80% of sampled temperatures.
The sampled air warms by about 5°C across four hours. Check your expected finish-hour forecast, not just the start.
Where the breeze came from
13 of 55 samples · 24%
Mean 16 km/h
The petals show how often the wind came from each direction at the sampled start hour. They do not predict the direction on race day.
A city-point wind rose cannot tell you which parts of the course will be sheltered or exposed. Use the live forecast and the organiser’s route map together.
Method: 55 ERA5 hourly samples at 09:00 local time, across 11 calendar days per year in 2021–2025. A 09:00 sample is used because the organiser has not confirmed a first start in this guide. Grid weather is modelled reanalysis, not an on-course station reading. Open-Meteo Historical Weather API . Snapshot generated 2026-09-29.
April conditions across all hours
April averages in Boston, based on 2022–2024 ERA5 history. These are monthly conditions, not a race-day forecast.
Monthly, all-hours averages for Boston, 2022–2024. Not past race-day measurements or a forecast. Rain is the share of historical hours with precipitation, not the chance of rain on race day. Source: Open-Meteo ERA5.
Explore running weather in BostonFind your starting pace
Start with your goal. Leave room for the day.
Set a finish time to compare an even-pace baseline with a one-hour weather snapshot. Use the changing forecast and course notes to decide where to be more conservative.
The baseline ignores hills and stops. The weather preview models one selected hour.
Explore the heat pace calculator3:15:00 finish · 42.2 km
View even-pace checkpoints
| Distance | Elapsed time |
|---|---|
| 5.0 km | 0:23:06 |
| 10.0 km | 0:46:13 |
| 15.0 km | 1:09:19 |
| 20.0 km | 1:32:26 |
| 25.0 km | 1:55:32 |
| 30.0 km | 2:18:39 |
| 35.0 km | 2:41:45 |
| 40.0 km | 3:04:51 |
| 42.2 km · Finish | 3:15:00 |
Boston Marathon FAQs
When is the 2027 Boston Marathon?
Boston Marathon is scheduled for 19 April 2027. Confirm the latest details on the official event website before travelling.
Is the weather shown a forecast for Boston Marathon?
The race-day forecast panel uses provider data for the event date when available. The 2021–2025 ERA5 race-window sample describes nearby calendar dates, not held race editions or a prediction for race day. Monthly averages, when shown, cover all hours of the event month.
What is the historical race-window weather like for Boston Marathon?
At 09:00 local, the 2021–2025 ERA5 calendar-window sample near Boston averages 10°C, 60% relative humidity and 12 km/h wind. The middle 80% of sampled start-hour temperatures is about 7–14°C. These are 55 city-grid samples from the event date ±5 days, not observations from held editions or a forecast.
Can the race-window history predict Boston Marathon weather?
No. It describes the same calendar window in 2021–2025. Use the live event-day forecast when available, check conditions through your own expected finish time, and follow the organiser for current start and course information.
Sources & race information
Weather-window data: Open-Meteo ERA5 Historical Weather API, sampled at the city grid for 2021–2025 and generated 2026-09-29. These calendar-window samples are not official race-day observations.
Guide reviewed . RunWeather is an independent guide, not the race organiser. Dates, waves and routes can change; the organiser’s latest instructions take priority. Course reference: 2026 reference course from RunWeather's curated catalogue. The next edition may differ; elevation is approximate.
Keep exploring
A race plan that goes with you.
Explore race planning and running forecasts in RunWeather. Keep your training and race-day preparation together.