TCS London Marathon weather.

Typically 10°C on race morning; dry every year. Race morning (07:00 to 11:00 local time) in London on race day in each of the last 10 years; the 2027 race is on 25 Apr 2027.

Typical
10°C (50°F)
race-morning average
Coolest
3°C (37°F)
lowest reading, 07:00–11:00
Warmest
19°C (66°F)
highest reading, 07:00–11:00
Wet years
0 of 10
rain, drizzle or worse
Humidity
77%
typical
Wind
12 km/h
typical, at 10 m

Race morning, 07:00–11:00

Year by year

Race dayAverageLow–highHumidityWindRainConditions
25 Apr 20268°C (47°F)5°C (40°F)–13°C (56°F)76%4 km/h0.0 mmOvercast
26 Apr 202512°C (53°F)9°C (47°F)–15°C (59°F)78%8 km/h0.0 mmOvercast
27 Apr 20248°C (46°F)7°C (44°F)–9°C (48°F)86%20 km/h0.1 mmOvercast
22 Apr 20237°C (44°F)3°C (37°F)–11°C (51°F)89%4 km/h0.0 mmOvercast
23 Apr 202212°C (54°F)11°C (51°F)–15°C (58°F)72%26 km/h0.0 mmOvercast
24 Apr 202110°C (50°F)6°C (42°F)–13°C (56°F)68%16 km/h0.0 mmPartly cloudy
25 Apr 202010°C (50°F)7°C (45°F)–13°C (55°F)77%13 km/h0.0 mmOvercast
27 Apr 20199°C (48°F)8°C (46°F)–11°C (51°F)65%37 km/h0.0 mmOvercast
21 Apr 201815°C (58°F)11°C (51°F)–19°C (66°F)78%11 km/h0.0 mmMainly clear
22 Apr 201710°C (50°F)9°C (48°F)–11°C (51°F)76%11 km/h0.0 mmOvercast

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 09:30.

Kit and pacing

What it means

  • Good racing weather

    Around 10°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.

  • It can be cold

    The coolest morning here dropped to 3°C. Pack gloves and a throwaway layer even if the forecast looks kind.

  • Expect wind

    Wind was 12 km/h on a typical morning here. Run in a group on exposed stretches, and aim for even effort rather than even splits: time lost into a headwind isn't all won back with it behind you.

  • The weather varies a lot

    Race mornings here have ranged by 8°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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