Runners, spectators and organisers will be keeping a close eye on the weather as the London Marathon gets under way on Sunday.
The latest forecast suggests largely settled conditions across the capital, with plenty of dry weather expected through the day and some sunshine developing after a cool start.
A chilly and misty start for some
Those heading out early on Sunday morning may notice a cold start, particularly in sheltered or low-lying areas. There is a chance of some overnight fog forming, especially in eastern parts of England. Any fog patches that do develop are expected to be fairly localised and should clear readily during the morning as daylight strengthens.
Isolated frost is also possible overnight, although this is more likely in rural areas outside the city. Within London itself, temperatures should remain a little higher, but early starters may still feel a chill during the pre‑race hours. Runners are advised to plan for cool conditions before the start, with warmer clothing useful while waiting.
Bright spells developing through the morning
As the morning progresses, fog patches should lift and break, giving way to variable cloud and increasing sunny spells. Skies are expected to be brighter at times, particularly late morning into the afternoon, helping temperatures to climb steadily.
READ MORE: Deep Dive: High-pressure, dry air and meteor showers
It is likely to feel noticeably warmer as the race goes on, especially inland areas away from the immediate coastline. While coastal locations often remain cooler under onshore breezes at this time of year, London should avoid the worst of this effect, allowing temperatures to rise pleasantly through the day.
Light winds and dry conditions
Winds are expected to remain light for most of the day, which is generally favourable for marathon running. The combination of dry weather and low wind speeds reduces the risk of additional cooling early on, but later in the race runners may become more aware of the sunshine, particularly in sunnier stretches of the course.
With little or no rainfall forecast, the overall feel of the day should be dry and bright, making for good viewing conditions for spectators lining the route. However, the increasing warmth means hydration will remain important for runners, especially as the sun breaks through the cloud.
A seasonable spring day
In summary, Sunday’s London Marathon is likely to take place under largely dry and settled conditions. After a cool, potentially misty start, brighter spells should develop, and temperatures will rise to feel warm for many by the afternoon. Light winds and dry weather point towards a pleasant, spring‑like day overall, well‑suited to one of the capital’s biggest sporting events.
Keep up to date with weather warnings, and you can find the latest forecast on our website, on YouTube, by following us on X and Facebook, as well as on our mobile app which is available for iPhone from the App store and for Android from the Google Play store.