The London Marathon 2026 full weather forecast: temperature and rain predictions for Sunday

You’ve trained for months, maybe years. You’ve carb-loaded. You’ve put together your motivational playlist. Now it’s time for runners in this year’s London Marathon to line up at the start line and tick a life experience off the bucket list.

Or, of course, you may just be out in London cheering on the runners. In either case, you’ll want to know about the weather forecast. All week London has been pretty balmy – a bit blustery, sure, but with plenty of blue skies and temperatures reaching the late teens.

Will the weather hold out for Sunday? Will it rain – or, worse still, be too hot? Find the full weather forecast for this year’s London marathon below.

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When is the 2026 London Marathon?

The race is on Sunday April 26, with non-elite runners starting from around 9.30am.

The weather forecast for the 2026 London Marathon

In short, the weather is looking shaping up pretty nicely on Sunday. It’s unlikely to rain, with the Met Office reckoning that there’s less than a five percent chance of precipitation.

When the race kicks off at 9am, the temperature will be around 11C. Throughout the day temps will rise to around 17C – which borders on a bit too hot. Runners (and spectators, but mainly runners), make sure you stay hydrated.

There is likely to be a bit of cloud cover at the start of the race (before 9am) and in the latter stages (after 2pm), but it shouldn’t be too windy. A 7mph will blow east-to-west.

Will London be too hot during the marathon?

When runners are arriving at the race in the early morning, the temperature will be around 9C. During the mid-afternoon peak (2pm-5pm), temperatures will peak at 17C.

Will it rain?

Get in: participants won’t have to worry about slippy surfaces and crowds won’t get drenched. Sunday is looking dry.

What is the best weather for running a marathon?

Well, the ‘best’ weather for running very much depends on each runner and the environment they’re used to. Dry weather is best, ideally without much wind.

Generally, 7C-15C is touted as a good temperature range for a marathon.

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