Boston Marathon weather.

Typically 8°C on race morning; rain in 1 of the last 10 years. Race morning (07:00 to 11:00 local time) in Boston on race day in each of the last 10 years; the 2027 race is on 19 Apr 2027.

Typical
8°C (46°F)
race-morning average
Coolest
2°C (36°F)
lowest reading, 07:00–11:00
Warmest
21°C (70°F)
highest reading, 07:00–11:00
Wet years
1 of 10
rain, drizzle or worse
Humidity
62%
typical
Wind
13 km/h
typical, at 10 m

Race morning, 07:00–11:00

Year by year

Race dayAverageLow–highHumidityWindRainConditions
20 Apr 20266°C (42°F)2°C (36°F)–8°C (47°F)63%13 km/h0.1 mmClear
21 Apr 20258°C (46°F)4°C (39°F)–11°C (52°F)52%4 km/h0.0 mmOvercast
22 Apr 20247°C (44°F)3°C (38°F)–9°C (48°F)50%15 km/h0.0 mmClear
17 Apr 20239°C (48°F)9°C (47°F)–10°C (49°F)92%12 km/h0.0 mmOvercast
18 Apr 20226°C (43°F)2°C (35°F)–9°C (49°F)60%8 km/h0.0 mmClear
19 Apr 202111°C (52°F)5°C (40°F)–15°C (59°F)66%6 km/h0.0 mmClear
20 Apr 20208°C (47°F)6°C (43°F)–9°C (48°F)59%14 km/h0.0 mmOvercast
22 Apr 201912°C (54°F)10°C (50°F)–14°C (56°F)95%13 km/h0.2 mmOvercast
16 Apr 20184°C (39°F)3°C (37°F)–4°C (40°F)90%35 km/h7.7 mmHeavy drizzle
17 Apr 201719°C (67°F)16°C (60°F)–21°C (71°F)62%19 km/h0.0 mmMainly clear

Each row is the race's date that year where we know it, else the same weekday nearest its usual date. Temperatures and humidity are averaged over 07:00 to 11:00 local time, rain is the total over those hours, and conditions are the commonest over the morning. The marathon starts at 10:00.

Kit and pacing

What it means

  • Good racing weather

    Around 8°C is close to ideal for a fast time. Shorts and a vest are enough once you're moving; bring a throwaway layer for the wait in the start pen.

  • Have a warm-day plan

    In the warmest of these years it reached 21°C by late morning. Decide in advance how much you'd slow down if the forecast is warm, rather than on the course.

  • It can be cold

    The coolest morning here dropped to 2°C. Pack gloves and a throwaway layer even if the forecast looks kind.

  • The weather varies a lot

    Race mornings here have ranged by 16°C from year to year. Pack for both, and settle your kit and pacing from the forecast in the last few days.

General guidance from past years' numbers. Check the forecast in race week.

The course 2027 dates and entry

Weather data by Open-Meteo.com, from its historical weather archive (CC BY 4.0).

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