The London Marathon 2023 Weather Forecast Looks PB-Friendly

Houses of Parliament in London with bank of grey clouds above
The weather forecast for the London Marathon predicts cloud cover and mild temperatures (Image credit: pcruciatti / iStock / Getty Images Plus)

When you’ve invested three or four months training for a marathon, it can be very disheartening when the weather intervenes on race day to make life harder for you. That’s one reason most major marathons are scheduled for spring and autumn, when mild conditions are more likely, and mild conditions is what runners are likely to enjoy at the London Marathon 2023.

That’s contrary to what the early forecasts for the race said. If there’s one thing I’ve learned from running the London Marathon five times, it’s not to pay too much attention to the long-term weather forecast for the race. The weather in the UK is too unpredictable to pin down 14 days in advance, and so early reports of a run-wrecking heatwave have disappeared.

Instead the weather forecast looks close to perfect, with the Met Office suggesting that temperatures will be between 9°C (48°F) and 12°C (54°F), with cloud cover and a 10% chance of light rain. Wind speeds are forecast to be under 10mph from the north, which shouldn’t play much of a part in the race since the London Marathon route mostly has runners traveling to the east or west.

Other forecasts largely concur with the Met Office’s predictions, though the BBC is more pessimistic about the odds of rain, putting them at 54%-70%. However, this is expected to be a refreshing drizzle rather than a race-ruining downpour. 

A spot of rain may even help you. When we spoke to Graham Ferris, strength and conditioning coach at Pure Sports Medicine, about running in the rain he told us “the rain can help stop your body temperature rising too high, which in turn promotes less thermic stress on the body, lower heart rate and perceived exertion.”

We all know how changeable the British weather can be, so we’d certainly recommend making sure you have some warm, waterproof clothes to wear at the start. You can take old clothes you’re happy to donate in the bins provided around the start line, or use a black binbag to keep yourself warm and dry while waiting in the start area. Another option is to get a cheap waterproof poncho. Here’s the Amazon UK search page with next-day delivery selected. You’re welcome.

Whatever you do use, make sure to pop it into a bin rather than discarding it on the floor for the runners behind you to trip over. It’s already crowded and chaotic enough at the London Marathon start line without having to worry you’re going to get tangled up in a disposable poncho.

Nick Harris-Fry
Senior writer

Nick Harris-Fry is a journalist who has been covering health and fitness since 2015. Nick is an avid runner, covering 70-110km a week, which gives him ample opportunity to test a wide range of running shoes and running gear. He is also the chief tester for fitness trackers and running watches, treadmills and exercise bikes, and workout headphones.