The Big Half
Race Day Weather
Warm day, variable winds ahead
Runners will face a temperature increase from 64°F at the start to 79°F by the finish, with average humidity at 59%. Wind will shift from a tailwind to crosswinds, and headwinds in miles 6 and 11 may challenge pacing. Adjusting pace early to accommodate the heat and maintaining hydration will be crucial, especially during the exposed segments.
Pace Calculator
Get forecast alerts for The Big Half
We'll text or email you when the forecast shifts — so you can adjust gear, pacing, and strategy. Max one per day.
Race Info
The Big Half is a half marathon through central and southeast London, organized by London Marathon Events, the team behind the TCS London Marathon. First held in 2018, the race starts on The Highway near the north side of Tower Bridge, loops east through Limehouse toward Canary Wharf, then crosses Tower Bridge and runs through Bermondsey, Rotherhithe, and Deptford to finish beside the Cutty Sark in Greenwich. The half is the centerpiece of a community-focused race day that also includes the one-mile Big Mile fun run and the New Balance Big Relay team event.
