London Marathon 2025: How to stay safe running in warm weather as advice issued to runners for 'mini-heatwave'

• The London Marathon will be taking place this Sunday.
• Tens of thousands of runners will be taking part in the event.
• The Met Office are predicting warm temperatures, with highs of 22C or 23C.
• The TCS London Marathon team have issued some guidance on how to stay safe running during the warm temperatures.

The 2025 London Marathon is taking place this Sunday (April 27), with over 56,000 runners registered to take on the challenge of crossing the 26.2 mile course.

Temperatures are set to soar this weekend, with the Met Office predicting highs of 22C or even 23C in London, although the sunshine sounds great for spectators, for runners the warm weather could make running a challenge.

To help reassure runners ahead of Sunday’s big race, the TCS London Marathon team have issued some guidance on how to stay safe running during the warm temperatures.

London marathon runners have been warned ahead of the warm weather this weekend. | Getty Images/Alishia Abodunde

What is the weather forecast for the London Marathon 2025?

The London marathon is shaping up to be a warm day, with highs of 22C or even 23C predicted by the Met Office. Whilst this weather sounds good for anyone watching the race, for those running, it could pose challenges, with the Met Office advising runners to ensure they stay hydrated and “consider applying sunscreen”.

Alex Deakin, Met Office presenter and meteorologist, said: “The 2025 London Marathon definitely looks better for the spectators because it is going to be getting quite warm by Sunday afternoon.

“First thing Sunday morning as you're waiting for the start It'll be quite fresh quite cool by the time the start gets underway. Temperatures probably 10°C or 11°C.

“Most of the day will be fine weather wise, there'll be some cloud but there will also be some sunny spells coming through and those sunny spells are likely to lift the temperatures through the morning So that by around midday we'll be looking at temperatures in the high teens 18°C or 19°C

“The winds are going to be fairly light but those temperatures will continue to tick up as we go through the afternoon probably peaking around the middle of the afternoon at 22°C maybe even 23°C.”

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How to run a marathon in warm weather?

Ahead of the warm weather predicted for Sunday, the TCS London Marathon team have issued advice on how to stay safe during the warm weather.

They recommend runners “wear loose mesh clothing”, advising against wearing multiple layers and not to attempt a personal best if the weather is unseasonably warm.

Runners are also advised to start slowly and if possible, run in the shade, whilst additional water will be provided and showers may be set up on the course to help cool down in hot weather.

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