Race guide

London Marathon Guide

The London Marathon is a fast, mostly flat road marathon held each April through central London. The course is famous for huge crowds and a downhill opening, which tempts runners to start too fast. The biggest pacing challenge is restraint in the first 10 km; cool spring conditions otherwise favour strong times.

Location
London, England
Distance
Marathon (42.2 km / 26.2 mi)

Typical conditions

Held in April. Typically cool (8–14°C) and often overcast or showery — good racing weather, though the occasional warm year catches runners out. Dress for a few degrees warmer than the start-line temperature once you are moving.

Course & elevation

  • Net-flat with a notable downhill in the first few kilometres around Greenwich, which makes the opening feel deceptively easy.
  • A flat middle and late race along the Thames, with the iconic Tower Bridge crossing near halfway and a fast finish on The Mall.
  • Crowd support is among the loudest of any marathon — energising, but it can pull you off pace if you feed off it too early.

Pacing strategy

  • Hold back on the downhill start. Banking time in the first 10 km is the classic London mistake and it costs far more in the final 10 km.
  • Settle into goal marathon pace by 5 km and aim for even or slightly negative splits.
  • Save something for the long, flat run-in along the Embankment — it is fast, but only if you have legs left.

Frequently asked questions

Is the London Marathon flat?

Largely yes — it is net-flat with a downhill start. There are no significant climbs, which makes it a popular choice for a personal best.

What is the weather like at the London Marathon?

It is run in April, usually cool and sometimes wet. Most years offer good racing conditions, though warm years do happen.

How should I pace the London Marathon?

Resist the fast downhill start, lock into goal pace early, and aim for even splits. The flat finish rewards runners who held back.

Plan your race day with Pacexis

Pacexis's race-day co-pilot pulls weather, course, gear, and pacing into one briefing the night before.

Explore Pacexis